Tag Archives: Natural dyeing

Persicaria tinctoria indigo extraction experiment

Hot vs Cold indigo extraction from fresh Japanese Indigo leaves

By Ashley Walker
Copyright 6th August 2018

Currently the main method of indigo extraction in use on internet Facebook pages is the 2 -3 day long soak in water. I believe this was the main method used commercially in the days before synthetic indigo wiped out the western market for natural indigo. Originally used to extract indigo from Indigofera tinctoria it is still used for small scale production in South Asia. The method is now used for Japanese indigo presumably because the traditional Japanese Method of composting the leaves is too large scale and time consuming for craft dyers. So it has been with some bafflement that I’ve seen the rise of this soaking method as I have always followed the Jenny Dean method which is even quicker.

We were introduced to plant dyeing through the pages of Jenny Dean’s “Wild Colour” and have used her recipe from this book for many years. It involves heating the leaves and can be done in two hours. Since we started to use this recipe we have tweaked it somewhat, discovering that there is no need to heat the leaves over 75 to 80°C to get maximum extraction. Another wrinkle is the need to allow the heated leaves to cool fairly rapidly. Large containers holding 20+ litres tend to cool too slowly and the indigo can be damaged. We did try one experiment when we cooled the extraction bath artificially but that was too quick and the results were very poor. An ideal extraction would be to heat about 1kg of leaves in 5 to 10 litres of water to 75°C and allow it to cool naturally over an hour. In our climate it will fall to around 40°C or less during that time.

So, now to the experiment which was a bit slap dash, but I am sure that it was systematic enough to have fairly good validity for a home dyer.

I picked just over 2kg of fresh Japanese Indigo of the Long Leaf variety which was showing no signs of any flower buds. This was divided into 2 lots of 1026g.

Persicaria tinctoria

Long Leaf Japanese Indigo showing leaf curl – a result of prolonged hot sunny weather.

Hot Soak Method (based on Jenny Dean)

Once batch of leaves was added to a large pan with about 8 litres of cold tap water (20°C) and then gradually heated with constant stirring to 75°C. This took exactly one hour and at the end the leaves had lost all of their fresh green tint and had turned almost black. The water was a very dark grey (a lot darker than usual in fact and I attribute this to a higher than normal amount of indigo in the leaf – a result of the weeks and weeks of hot sunny weather we have had this summer).

The leaves were then left to soak for one more hour, after which there was an indigo bloom at the surface and the water had darkened further. The leaves were removed (by straining through old tights) and 4 tablespoons of household ammonia were added with an immediate colour change to dark yellow/green. The liquid was then oxygenated by pouring from bucket to bucket about 20 times during which the liquid darkened to a green black. A small quantity of the liquid (viewed from above in a white plastic cup) looked olive green.

Indigo extraction from Japanese Indigo Hot and cold methods

Comparison of Hot and cold indigo extraction after 1 hour of soaking but before straining.

Cold Soak Method

The second batch of leaves was placed in a plastic bucket filled with about 8 litres of hot tap water (57°C). I used hot water because I did not wish to wait more than 24 hours. At this temperature the leaves become slightly cooked and release cell contents into the water quicker. The bucket was then set aside for 24 hours. After 1 hour the temperature had fallen to 44°C, the leaves were still quite green and the liquid was much paler and bluer than the hot extraction at the same stage. See image above.

After 24 hours the leaves were still greenish, although they had darkened somewhat. There was a lot of indigo scum on the top leaves. The liquid was grey with a blue tint. The plastic bucket was stained blue. Generally the results so far looked good, with much more blue visible than in the Jenny Dean method.

Indigo extraction from Persicaria tinctoria

Cold indigo extraction after 24 hours. Lots of indigo bloom on leaves.

Indigo extraction from Persicaria tinctoria

After leaves are removed, alkali (ammonia) added and liquid aerated.

Extraction of indigo from Persicaria tinctoria

Comparison of colour of water after extraction.

Leaves of Persicaria tinctoria after indigo extraction.

Colour of leaves after cold soak for 24 hours.

 

Indigo stained bucket

Empty plastic bucket used for 24 hour cold soak now stained with indigo.

The leaves were removed and about 4 tablespoons of household ammonia were added and the colour immediately changed to yellow green. The liquid was then oxygenated, by pouring back and forth between buckets about 20 times. During this process the liquid darkened until it was nearly black. A small quantity looked blue/green.

Dye test

Both extracts were then heated at the same time in separate pans to 50°C, the ideal temperature for dyeing wool, and spectralite reducing agent (thiourea dioxide, thiox) was added (one and a half teaspoons) to each pan. They were then left for about 2 hours to give ample time for the indigo to be reduced. The pots were then reheated to 50°C and an identical skein of wool (Corriedale) was added to each. Both pots were then gently stirred to promote even dyeing and the skeins were removed after 20 minutes.

Results

Initially the colour of the skein from the Jenny Dean (hot) method looked darker but on drying no difference could be detected.

Dye test. hot and Cold extracted indigo from Persicaria tinctoria

Test dye showing relative strengths of dye bath from Hot and Cold extracted indigo.

Conclusions

The amount of indigo extracted appears to be the same for both methods. However, heating, cooking and stirring the leaves increased the amount of fine particulate plant material in the liquid which increased the amount of sludge in the bottom of the dye bath.

I should clarify I don’t use lime (as a combined alkali and flocculating agent) to obtain a dried indigo pigment from my dyeplants. Any indigo I don’t use straightaway for dyeing, I store as liquid sludges. But I can see that for people who do use lime, the cold soak is advantageous because the resulting indigo pigment would contain fewer impurities than the hot soak because the liquid extract after straining is purer. For myself I’m quite happy to continue using my modified Jenny Dean process as it is fast and reliable.

Postscript

Out of interest I also decided to compare the Long Leaf Japanese Indigo to Woad. I processed a similar quantity of Woad leaf according to the 24 hour soak method in the experiment. Another wool skein was dyed in nearly identical conditions and the results prove to me that Woad can actually produce more indigo than Long Leaf Japanese Indigo.

Wool dyed with indigo extracted from Persicaria tinctoria and Isatis tinctoria

Comparison of strength of indigo extracted from Long Leaf  Japanese Indigo and Woad.

A note on alkalis

There has been a lot of controversy about which alkalis produce the best results. I have tried most of them and found that what is important is the pH not the exact chemical used to get there. Washing soda is the weakest and produces very poor results. Household ammonia is excellent and relatively safe, provided you don’t get it on your skin or breathe it in. Calcium hydroxide (lime) is good and has the added benefit of soaking up the indigo precipitate and settling it to the bottom fast (flocculation). Sodium hydroxide is also good but is very corrosive – a danger to skin and textile.
Whenever using strong alkalis you must take safety precautions: wear gloves; avoid splashes; don’t ever add water to dry alkaline powders or granules, add the powder to water; label colourless solutions and store safely; never leave sodium hydroxide solutions unattended for curious animals or children to explore (it is colourless and odourless and very corrosive indeed).

References

Wild Colour by Jenny Dean

Susan Dye and Ashley Walker

The Natures Rainbow garden 2018 – Part one

by Ashley Walker
Copyright August 2018
Banner photograph copyright Sharon Cooper

On the 9th August, after two months with barely a drop of rain, the heatwave and drought in the South East of England may finally have come to an end. Despite regular watering the unnatural weather has taking its toll on our dye plants. For the first time our woad plants are being eaten by Cabbage White butterfly caterpillars (Large White Pieris brassicae and Small White Pieris rapae) and more recently by flea beetles (genus Phyllotreta). I guess the critters were getting desperate to find plants with a bit of juice in their leaves. The weather is having an impact on me as well, I have to water the indigo nearly every day and keeping the rest of the garden needs water too so I’m spending hours each week that I’d rather be spending on writing or dyeing.

This is the first part of a two part post on observations of the dye plants in our garden. This one deals with the plants we have been growing for more than a year. The second part will cover new plants.

European Woad – Isatis tinctoria

Isatis tinctoria being eaten by Large White butterfly caterpillars

These Large White caterpillars managed to eat the whole woad leaf, leaving only the midrib behind.

We have grown Woad for about 12 years now and for the first time our plants have been attacked by caterpillars and flea beetles. This makes a change from the usual small black slugs which put a few holes in the leaves but seldom do any serious damage.

Isatis Tinctoria leaf with eggs and lava of Large Cabbage White butterfly

A cluster of Large White butterfly eggs on the underside of a woad leaf

Isatis Tinctoria being attacked by Flea Beatles

Shiny black small Flea Beatles can slowly chew their way through a woad leaf leaving it like a sieve.

Isatis tinctoria

Woad flower spike August 2018 – from seed to flower in one season as a result of pampering.

I expect that the extraordinary hot weather is to blame with the butterflies and beetles probably acting in desperation. Although the flea beetles appear to thrive, the caterpillars have had a much harder time digesting the unpalatable leaves and most of the newly hatched critters have simply died, leaving a few small holes in the leaf. Only one plant had its leaves reduced to its midrib but even this one will survive as it is now putting out new growth. Interestingly it appears to be only the plants I have watered which are being eaten. There are a few plants which never get watered and these are looking fine.

A few people have asked about growing Woad in tubs or containers and this year we’ve had a few in containers ourselves and this has revealed a problem. One of our plants grown in a container in good compost and watered and fed regularly has grown large and is currently putting out a flower spike which will drastically reduce the amount of indigo in its leaves. Its very unusual to see Woad flowering in August so I can only assume we have pampered it too much – given it the ability to grow large enough to flower in one season. So if you are growing Woad in containers don’t give them too much fuss!

Chinese Woad – Isatis indigotica  

Isatis indegotica

Chinese Woad – about as big as it gets before flowering

Isatis indigotica

Planted out in April these Chinese Woad immediately produced flower stems

We have been growing this for two years now, desperately trying to find out how to stop it flowering a few months after planting. From what I’ve read I’m in good company and this is the chief reason Chinese Woad has not caught on as a source of indigo, despite the fact that it could potentially produce as much dye as Japanese Indigo. Some of the literature indicates that botanists think Isatis indigotica is basically just a variety of tinctoria (European Woad). However, if that is so it has evolved away from tinctoria to a considerable extent. Indigotica is clearly adapted to a much warmer climate and although still nominally a biennial it behaves much more like a half hardy annual. It will flower at any time of year, even in winter, so its rosette stage is always very short and the plant never gets very big. The leaves are a paler blue-green than European Woad and its yellow flowers will continue to be produced throughout the year provided the plants are watered and taken care of. Once the plant starts to flower the larger rosette leaves die off leaving only small leaves on the plant which are probably no good for dyeing. According to the Handbook of Natural Colorants, indigotica will be triggered into flowering if the night time temperature falls below 5°C, which makes it almost impossible to grow the plant to any respectable size here in the UK. Even in Mediterranean climates the plant can only usefully be grown in the Summer. From my experience the plant will flower even if you just look at it the wrong way so I’m coming to the conclusion that it’s not worth the effort. It does grow very quickly however and if you were to grow it en masse and harvest the leaves before it flowered it might just provide a return for your efforts.

Another problem with Chinese Woad is its susceptibility to pests. Caterpillars and aphids like it very much and can easily destroy your plants.  And you guessed it, significant insect damage will also trigger flowering. In a mad moment I decided to see if Chinese Woad tasted any nicer than European Woad. But the taste test settled nothing, both plants are extremely bitter and fiery. I obviously don’t have the finer tastes of Cabbage White butterfly caterpillars!

Japanese indigo – Persicaria tinctoria

Persicaria tinctoria - Long Leaf variety

Long leaf variety of Japanese Indigo with curled leaves to protect itself the prolonged hot sun of 2018

This year we are growing the same three varieties as last year – Long Leaved, Broad Leaved and an Intermediate Leaved white flowered variety. There appears to have been no interbreeding from last year. This year the difference between the long leaf and broad leaf varieties is stark. The Long Leaf plant is very vigorous with dark green leaves. The Broad Leaf variety took a long time to get going as usual and suffered from its leaves turning red. I was initially confident that the red colour was partly due to the hot sunny weather we were having in early summer – the slow growing plants were getting roasted. But after a good feed (with chicken manure pellets) the plants started growing quickly with the new foliage a nice mid green despite the continued hot sunny weather. So a bit of a chicken and egg situation: was it the lack of fertilizer that caused the leaves to redden or simply that the young plant leaves, growing slowly, were getting a longer exposure to the hot sun?  The Long Leaf variety reacted differently to the hot sun with leaf curling , something I had seen last year but only on plants grown in the greenhouse.

Persicaria tinctoria

A bed of intermediate White flowering Japanese Indigo.

Persicaria tinctoria

Newly planted out Broad Leaf Japanese Indigo with sun reddened leaves.

Thus far we have only harvested the Long Leaf variety and used it in a little experiment comparing Jenny Dean’s extraction technique with the more often used long soak in cool water. The results will be written up in a later post. What I have also noticed is that we are currently getting a considerably better production of indigo from Woad than the Long Leaf variety of Japanese Indigo. Woad is well known for giving better results when the weather is hot and sunny. If the climate change predictions are correct and we continue to have hot summer weather then I think we would be better to return to growing mostly Woad. The Long Leaf variety of Japanese Indigo produces the least amount of indigo dye of the three varieties (see comparison here) but it does produce larger plants so perhaps still produces an equivalent amount of indigo per square metre.

Madder – Rubia tinctorumRubia tinctorum berries

Once again this year the madder plants are producing masses of berries. This is the third year running. In the previous 10 years or so the plants produced only a few. I have no explanation as to why this is.  I’ve grown plants in different soil, in planters and in the ground and all plants are doing the same. A result of the weather?

Rubia tinctorum

Madder plant obtained from Southwark Cathedral in early 2018.

This year we obtained a new madder plant sourced from Southwark Cathedral dye garden. The plant is quite different to plants I have been growing up to now (all of which were derived from a single seed over 10 years ago). This new plant has paler leaves with a different shape and it flowers about 3-4 weeks later. It will be interesting to see if the root yield is also different. I’m pleased to have been able to increase the genetic diversity of our madder as I’ve always propagated by root stem cuttings or from seeds from my own plants.

Wild Madder – Rubia peregrina

Rubia peregrina

Wild Madder in flower – Early July

We’ve been growing this plant for nearly three years now. It’s an evergreen but the tops do not appear to be totally hardy in the UK climate and were damaged by the winter frosts. This is the first year in which the plants (originally obtained from a wild flower nursery) are starting to look a bit happier. They are putting out new shoots from underground stems and flowering for the first time. It remains however a very slow growing perennial and I think it will take longer than Common Madder to produce a good root harvest so we are leaving it for another year.

I was given some seed from a friend from some wild plants growing on the south west coast which nearly all germinated though it did take well over a month before the first shoots appeared.

Saw wort – Serratula tinctoria

Serratula tinctoria

Saw-Wort plants with yellowing of leaves.

Serratula tinctorum

A self seeded plant with dark green leaves growing next to the transplanted ones with yellow leaves.

This native  plant continues to be disappointing. Not only do the plants remain small but about half of them suffer from bad yellowing of the leaves once planted out in the garden. I have tried practically everything to remedy the problem – fertiliser, Epsom salts and seaweed extract. There are some self-seeded plants which look very healthy so I do wonder if the roots are somehow getting seriously damaged during transplanting. It also remains likely that there is something wrong with the soil itself as other plants (Genista, a red scabious and a Purging Buckthorn shrub) are similarly affected.

Serratula tinctoria dye comparison

A comparison of our main yellow dye plants. Top is Weld, Bottom Right is Genista and Bottom Left is Saw-Wort

We did try dyeing with the Saw Wort this year and obtained a good buttery yellow. We were hoping it would be a nice lemon yellow like Weld and Genista so were a bit disappointed with that too.

Dahlia species

Dahlia Species

Bumble bee on single type dahlia grown from seed.

Dahlia Species

Dark Red Dahlia giving pinky purple and greens. Possibly “Nuit d’Ete” or “Black Cat”

The colour of Dahlia flowers has an effect on its dye but we did not appreciate by just how much until this year when we tried using some deep red flowers to dye with. We obtained nothing like our accustomed strong yellows with acid pH and strong orange with alkaline pH. This time we got green with alkali and blue/purple with acid indicating that the dyes in this dark red flower were the same as you find in red cabbage and some other red flowers. These dyes, although very pretty, are not light fast. Over the years of growing Dahlia we have narrowed down the varieties that produce the best results for the home dyer. These are yellow or orange double flowering pom pom types. The pom pom flowers are longer lasting and produce more dye – some pom poms are very large and yield a lot of dye but bees and pollinators are unable to assess the nectaries. We have tried to stay away from these but there’s no doubt they are the best for dyers.

Tansy – Tanacetum vulgare

Tanacetum vulgare

Tansy needs regular watering for healthy plants.

Often used by Scottish dyers as a source of yellow dye this plant has been growing in our garden for several years now but largely unused because the plant wasn’t very vigorous. There was never enough plant material to harvest and the flowers were disappointing. This year we planted a bed of Japanese indigo alongside so the Tansy benefitted from being regularly watered. The resulting Tansy flowers have been lovely so if you’re growing them keep them watered for best results.

Perennial Coreopsis –  Coreopsis grandiflora varieties e.g. Golden Joy, Sun Ray, Early Sunrise

Coreopsis grandiflora

Perennial coreopsis – plant breeders benefitting the plant dyer.

Coreopsis grandiflora

Bright orange on alum mordanted wool blanket.

These are double flowering perennials with deep orangey yellow flowers which produce a lot of dye. They are not as hardy as the growers would have you believe as half our plants died during the winter and only a few have recovered enough to put on a good show this year. However, many can be easily grown from seed so are not too expensive to grow. They make excellent bedding plants and produce a fabulous orange dye from the flowers. An example of the plant breeders unwittingly aiding the home dyer.

Dyer’s Alkanet – Alkanna tinctoria?Alkanna tinctoria

Alkanna tinctoria

Alkanet root. Bottom tip has had thin outer black bark removed revealing the dissapointingly white root.

This is the third year of growing and though I have not tried to extract any dye from its roots I am deeply disappointed to find that the roots are not red as they should be. I was suspicious as soon as I started to grow the plant from seed bought from the German Company Rühlemann’s. The plant seemed too vigorous with over large leaves and not hairy enough, but I persisted with it until it flowered. The flower shoots were tall (up to about a metre high) and not at all like the creeping wild flower growing around its native Mediterranean. The flowers when they finally appeared were the only part of the plant that looked like the pictures of Alkanna tinctoria seen all over the internet but the roots? The roots were white!

Doing some reading around this ancient dye plant I find that its qualities as a medicinal plant derive solely from the coloured substances in the root which were used as a dye, cosmetic and bio stain so you can imagine the way I feel after lavishing attention on this plant for the last three years only to find the roots are white! Recently I discovered one internet comment on the plant that says the cultivated version of the plant does not produce as much dye as the wild type. Well that’s some understatement. Of course it is possible that lavishing attention on the plant was entirely the wrong thing to do and I should have left it alone but it seems more likely that the growers have simply selected the seed year after year from the largest prettiest plants and in so doing have bred out the qualities that gave the plant its historical value.

Just to confuse matters Alkanna tinctoria has been and is also known as “Anchusa bracteolata, Alkanna tuberculata, Alkanna lehmanii, Lithospermum lehmanii”, and has been given various common names as follows Alkanna Radix, Buglosse des Teinturiers, Dyer’s Bugloss, Henna, Orcanète, Orcanette, Orcanette des Teinturiers, Orchanet, Radix Anchusae. Rühlemann’s who sell the seed are now calling it Alkanna tuberculata. There is certainly confusion on the identity of all these plants. Are they all the same or not. If there are any botanists out there  who can get to the bottom of this please please get in touch!

References

Philip John and Luciana Gabriella Angelini – Indigo – Agricultural Aspects. Chapter 7 of Handbook of Natural Colorants  Edited by Thomas Bechtold and Rita Mussak. Wiley Series in Renewable Resourses. (Available as free download).

Rühlemann’s  This German herb plant and seed supplier has a number of dye plants for sale including Chinese Woad and Long Leaf Japanese Indigo but it is primarily interested in the medical properties of the plants it sells and I get the impression they know little about plant dyeing.

The Natures Rainbow Year – (and its only half way through!)

An article by Susan Dye and Ashley Walker
© copyright 2018

2018 is turning out to be our most successful yet.

The year began with our good friend Brian Bond joining us to deliver a two day workshop in Ipswich in late January with the International Felters Association (see above). Susan was involved in much mordanting in preparation. This was our second major plant dye workshop away from home, and dependent on friends or family to help us with transport. Hard work packing an ‘all singing all dancing’ workshop and the three of us into a single hatchback vehicle (albeit a large one, thanks Brian!). Quite stressful but very well worthwhile, as the students were terrifically motivated and created a full palette of wonderful colour on the finest merino tops.

Also in January we had confirmation that Southwark Cathedral had invited the London Guild of Weavers, Spinners and Dyers (WS&D) to demonstrate plant dyeing as part of London Craft Week in Mid-May. Susan was asked to coordinate the project, having held a successful mini natural dye demonstration there as part of the biennial London Guild exhibition last November.

Preparations for all this activity took place mostly in the winter and early spring when the weather was too cold or wet to work outside on the dye garden

In between scoping and planning the London Guild event at Southwark, Susan gave talks on plant dyeing to the Chelmsford Embroidery Guild, on the red dye from madder for the Cambridge Guild of Weavers, Spinners and Dyers and, closer to home, a talk on the horticulture of dye plants for the Wymondley Gardeners Group. Had the snow in early March not intervened there would have been another talk on the history of Norwich Dyers to region 7 of the Quilters Guild.

London Craft Week event at Southwark Cathedral with the London Weavers, Spinners and Dyers Guild

The Shard overshadows our colour splash at Southwark Cathedral

Susan spent much of April mordanting and test dyeing fabric and yarn for the London Craft Week event, which was to be held outdoors in the Churchyard in mid-May. Fortunately the weather improved and we were blessed with two sunny breezy days. With help from textiles graduate Hannah Sabberton, Susan and I carried Hitchin grown fresh woad and dry Weld, Indigo dye solution, mordanted fabric yarn and fleece, samples, display materials and goodness knows what else (kitchen sink comes to mind!) on the train and bus into Central London at rush hour. We are resourceful public transport travellers with trolleys and backpacks and all arrived safely! Mercifully all the pans and heaters had been supplied by London Guild members based not too far away (thanks to Penny and Diane). Also there were many, many lovely dyers from the Guild who shared the demonstrating. All told there were twenty two volunteers across the two days. We spoke to people from all over the world, from London and other parts of the UK. Tiring but very satisfying to see the rainbow of colours we achieved with just the three medieval ‘grant teint’ plant dyes: Madder, Weld and Woad.

Susan managed to escape a couple of times down to the British Library where she loves to do research on the history of dyeing and in particular the 19th Century “Norwich Red”. An article to be published in the Autumn issue of “The Journal of Weavers, Spinners and Dyers” will detail her findings so far. We have also been asked to write an article on growing dye plants with a particular emphasis on small gardens and container growing. This should appear in the next issue of “British Fibre Arts” along with a profile about ourselves. The Editor Rainy Williamson made us think about what we do and why we do it. I was particularly reminded that many people do not have access to a garden or allotment and may only be able to grow dye plants in small spaces. I immediately set about making and planting up some large-ish containers with suitable dye plants to see how they responded. And then we got to thinking that apart from a couple of small demonstrations and the regular workshops for our local guild we’ve never made an effort to share our skills in plant dyeing with the local population. So Susan quickly got on the phone and asked the Hitchin Festival organisers if they still had some slots left in their programme and lo and behold, (thank you Keith)  we were found a slot in the programme.

Indigo Blue, Weld and Chamomile yellow and Greens produced by overdying yellow with blue and blue over yellow

Results from the green overdye experiment done at the Herts Guild of Spinners Weavers and Dyers Workshop

Meanwhile we had another workshop for our local Guild in North Herts to get ready for. This was based around an experiment investigating the notion that a better green is obtained if wool is dyed first with indigo and then weld (yellow) rather than the other way round as we have traditionally done it. Various accomplished plant dyers had reported this finding and we wanted to check it out. The workshop produced some fantastic greens and, somewhat to our surprise, the blue overdyed with yellow did indeed produce the best green.

While all this has been going on I’ve been working hard on the Natures Rainbow dye garden, getting it into shape to satisfy the North Herts District Council allotment inspector (Grounds Maintenance Monitoring Officer). Because we are growing a most unusual set of crops some of which look remarkably like weeds we

Rubia tinctorum

Madder is closely related to the weed Cleavers or Goosegrass. It looks and behaves much the same but is altogether larger in stalk and leaf and has berries instead of hard seeds.

Ransoms Rec Allotments, Hitchin

The Natures Rainbow allotment plot in early June.

have to make the plot look as tidy as possible. Madder for example is a close relative of the weed Cleavers and has the same sprawling habit and Weld is generally classified as a weed anyway. In addition, we leave our second year Woad plants to go to seed, so we have stock for the following year and this too raises eyebrows.

Asperula tinctoria

Dyers Woodruff in flower

We also decided early on this year that if we are going to continue giving talks and writing articles about growing dye plants then we need to expand our experience and grow some of the more unusual dye plants so we sent off for more seeds including Chinese Woad, Wild Madder, Field Madder, Ladies Bedstraw, Blood Root and where we couldn’t get seeds we ordered plants. These include Dyers Woodruff, Black Oak, and Smooth Sumac (Rhus glabra).

Quercus velutina

Our new Black or Quercitron Oak Sapling. The inner bark of this North American tree produces the dye quercitrin which for a while was a major industrial source of yellow dye. Of course it will be many years before we can harvest any bark from this specimen!).

Reseda luteola

Honey bees are particularly fond of Weld

 

 

 

 

 

 

 

 

As a beekeeper I’m also very interested in growing plants that are also good for all kinds of bees so I’ve been very gratified that many of our dye plants are also fantastic bee plants too, Weld and Japanese indigo are two of the best.

Rhus Glabra

Smooth Sumac from North America, the dried leaves of which contain 25-27% by weight of tannins.

Look out for more blogs detailing some of the events mentioned here but you might have to wait until things calm down a bit before we get time to write them!

Inula helenium

Elecampane – Inula helenium

An article by Ashley Walker
© copyright 2018

When we first became interested in growing and using dye plants we came across an entry in “Traditional Scottish Dyes and how to make them” by Jean Fraser. This seemed to us to be very exciting because it offered a tantalising alternative blue dye to Woad indigo.

Traditional Scottish Dyes and how to make them by Jean Fraser

Page 69 from Jean Frasers book – Traditional Scottish Dyes and how to make them.

Traditional Scottish dyes and how to make them by Jean FraserWe immediately set about obtaining some seeds which were readily available as Elecampane is a popular garden flower and ancient medicinal herb. Our first lot of seedlings were all eaten by slugs but the second batch (protected until they were larger) survived to produce two small beds.

It took a number of years for the plants to reach full size but by this time we had realised that the likelihood of obtaining blue from the roots was very unlikely and we had discovered Japanese Indigo so did not think it worth even trying. We kept the plants because every year we are rewarded with a sunny display of glorious yellow flowers which act as magnets for bees of all kinds. These tall plants with giant leaves are low maintenance and just take care of themselves.

Inula helenium

Honey bee on Elecampane flower.

The Dye garden has grown over the years and we are getting to the point that every plant species we grow has to justify its presence by being a proven source of plant dye. But still, the mystery of Jean Fraser’s entry stuck in our minds so this year I decided to give it a go before the plants started to grow.

Three of the incomplete “no details or quantities given” recipes mention whortleberries and one recipe Elder (presumably berries) as additives to improve the colour. We know by now that most black berries can give pinks, lilacs and mauves with a good alum mordant but they are not lightfast, iron mordants are best at prolonging the life of fugitive dyes and the fourth recipe mentions iron so we thought it worth obtaining some whortleberries . What are whortleberries?

Wikipedia suggests they are one of three possible members of the Vaccinium family:

Vaccinium myrtillus, bilberry, or blue whortleberry
Vaccinium vitis-idaea, lingonberry or red whortleberry
Vaccinium uliginosum, bog whortleberry/bilberry

All three plants grow commonly in Scotland but we think it is a reasonable guess that the name refers to the bilberry V. myrtillis or uliginosum as vitis-idaea is a red berry. The closest source of berries we could get hold of were supermarket blueberries (probably Vaccinium corymbosum). Not as good as our native bilberries as they only have a blue black skin and internal pale green flesh. Our native species are blue/black throughout.

Experiments

Initially we tried a number of variations:

  1. Fresh chopped and bruised roots heated with and without blueberries
  2. Fermented chopped and bruised roots with and without blueberries
  3. Samples of unmordanted, alum mordanted and iron mordanted wool were added to each of the dye pots (the root and berry material were not removed).

The roots of elecampane are white with a yellowish skin and black bark which is not attached to the root and is easily washed off. There appears to be no colour in the root at all!

Inula helenium

Elecampane root

Inula helenium

Elecampane cut root

Because of this lack of colour we had long suspected that the only possible source of colour would be from tannins in the root reacting with the iron mordant to give a grey. We suspected that in Scotland grey was often called blue and with the addition of some whortleberries a bluish grey could be obtained though it would fade to grey over time. As there are many other sources of tannin in the dye plant world we were sceptical that Elecampane root would give us anything worth having.

Results

The results were fairly conclusive in that the only significant colour change occurred with the iron mordanted wool where a silvery grey was obtained from the fresh root and a yellowish grey from the fermented root. The unmordanted wool stayed white and the alum mordanted wool turned a very pale yellow. The addition of blueberries made little difference.

Inula Helenium dyed wool

Right: iron mordanted wool in fresh root dye bath. Left: Iron mordanted wool in fermented root dye bath.

Inula helenium treated woth iron mordant

On the left cut root treated with iron mordant. On the right untreated root.

Painting an iron mordant solution onto cut plant material usually shows up the presence of tannins fairly rapidly but sometimes it takes a few hours to get a colour change. The elecampane root had to be left overnight before the change seen here on the left took place. Other additives mentioned in the recipes are salt and ash. Dipping a cut root in salt had no effect but adding a tiny amount of sodium hydroxide (an alkali in wood ash [lye]) to the cut root turned it immediately yellow and after 24 hours a yellowish dark grey. We did not use any of this alkali in our experiments as we were particularly interested in obtaining a neutral or blue grey but it looks like adding the alkali could aid in getting a darker colour.

Once we were happy we could get this neutral grey we went ahead with dyeing a large skein of hand spun yarn (about 100g) mordanted with 1g of ferrous sulphate*. This was added to a dye bath made from about half a kilo of chopped and bruised Elecampane root heated to around 90°C and left for one hour then strained to remove the solids.

Inula helenium dyed wool

100g skein of hand spun iron mordanted wool dyed with Elecampane root.

OK, so no blue, but a good neutral grey is hard to obtain as most tannin rich plants have additional dye stuffs and the greys obtained are tinted with yellows or browns. Elecampane is almost free of any of these contaminants. As any designer will verify grey has the ability of amplifying adjoining colours making them seem brighter than they really are. A dye garden without a source of grey would not be complete so the Elecampane stays!

Inula helenium

Elecampane in full flower

*The iron mordanting is done according to Liles method using the same quantity of oxalic acid as ferrous sulphate. The Oxalic acid prevents the iron from oxidising from the yellow-green ferrous sulphate to orange ferric oxide (rust).

References

“Traditional Scottish Dyes and how to Make them” by Jean Fraser. Illustrated by Florence Knowles. © 1983, 85 and 96.

“The Art and Craft of Natural Dyeing – Traditional Recipes for Modern Use” by J. N. Liles. © 1990

Colour in Winter 2018

In January two years ago I ran a plant dye workshop for Region 5 of the International Feltmakers  Association. One thing leads to another and … by way of the IFA AGM last Spring, I was invited to run a similar workshop this January for the Region 7. And what a delight it was!
Thank you to Sally Sparrow for organising the event.

With my friend Brian’s most excellent vehicle (I don’t run a car), and not a little anxiety as to whether I had packed everything we needed, we installed my dye studio in a scout hall in the outskirts of Ipswich for the weekend.

Dye woerkshop2-small

The venue was large and well appointed with power sockets for my preferred heat sources – portable electric induction heaters (you can see them in the background in the picture above).

By the end of the weekend nine enthusiastic participants had applied a good palette of natural colour onto nearly 2kg of pre-mordanted fine wool and silk. If you would like to know more and see some great photos, check out Kim’s blog at flextiles here and here. Kudos to Kim, for the excellent write up!

We used home grown madder for pinks and reds, home grown weld for acid yellow and for blue we used bought in woad powder and natural indigo (because at this  time of year you can’t use fresh leaf). We also added in some oranges from dyer’s coreopsis and warm yellows from dyer’s chamomile, both from stock of our home grown, dried flowers.

Here are just some of the colours we obtained.

blog post washing line

 

Chamomile on silk-small

 

 

Madder recipe A on Woo-smalll

 

 

 

 

 

 

 

My aim was for people to get lots of hands on experience working with the dyebaths, to be free to spend most time on the colours that most interested them and get some theory and tips on good practice. I also like to make sure everyone goes home with enough fibre to use in a project. And finally, because I can’t resist the technical detail, there are handouts to read later.

blog post image drying rack

The workshop couldn’t have run without my two helpers. My partner Ashley ran the indigo vats at one end of the room while I set up madder and weld dye pots at the other. Brian Bond, a longstanding friend and collaborator, was invaluable as all round helper.

For inspiration, Brian brought along his glorious plant dyed and hand spun yarn and knitted garments to display. Ashley brought his current work in progress – darned squares of which he needs to make 144 to complete a blanket.  And I set out my collection of fabric and thread samples.

This kind of workshop has long been a regular feature of my local Spinners Dyers and Weavers Guild.  We usually hold these events outdoors on a long summer’s day which works really well for rinsing and drying. I’m looking forward to running the next plant dyeing day for the North Herts Guild of Spinners Dyers and Weavers on Saturday 26 May 2018.

Contact me if you are interested in hosting a plant dyeing workshop. I am open to designing events to suit specialist audiences.

Note on blue: We were using a combination of commercially produced woad powder and natural indigo. To save time at the workshop, these were made up into separate pre-reduced stock solutions.  We discovered that the woad powder was considerably less concentrated  than the natural indigo. As a result the woad stock solution was over-reduced. The natural indigo produced some very dark blues (see below). Whereas the woad vat was over-reduced and it wasn’t possible to apply a deep colour, no matter how many dips we did. We plan to do a controlled experiment comparing the strength of different commercially available woad powders – so check back for more details.

small dark indigo drying

Persicaria tinctoria

Three strains of Japanese Indigo tested and observations on indigo extraction

An article by Ashley Walker
© copyright 2017

This year I had planned to carry out a tightly controlled experiment to look for variation in the amount of indigo produced by three fairly distinct strains of Japanese indigo. However due to a prolonged and still undiagnosed illness, my plans were thwarted and the experiment did not work out quite as I had hoped. However, on 12th and 13th October 2017, with help from Brian Bond another keen plant dyer, I did manage to complete a test of the three plants although the results are not directly comparable due to different planting times and maturity of each variety.

The strains

Broad or Rounded leaf indigo

Persicaria tinctoria

Round or wide leaved Indigo. Directly sown bed

Grown from seed originally from the USA (from fellow natural dyer Pallas Hubler in Washington State on the west coast) who sent a few seeds over to Brian in 2013. We have been growing and saving seed from this strain ever since so it is possible that it has become adapted to growing in our soil.

  • Late flowering (October into November)
  • Pink Flowers
  • Compact short flower stems
  • Wide short or rounded leaves
  • Foliage pale to mid green
  • Easily damaged by high nitrogen levels in the soil. Grows poorly in cool overcast weather.

Long leaf indigo

Persicaria tinctoria

Long leafed Japanese Indigo in full flower.

Seed for this was obtained from the German supplier Rühlemann’s. Unfortunately this was in full flower by the time I was able to harvest it for the test and from previous experiments I know that once indigo has committed itself to flower production the amount of indigo in the leaf falls dramatically.

  • Large long pointed leaves
  • Pink flowers
  • Long delicate flower stalks
  • Early flower (September-October)
  • Dark green leaves
  • Very tolerant of high nitrogen in the soil and generally more robust.

An in-between white flowered strain

Persicaria tinctoria

Intermediate white flowered Japanese Indigo

Persicaria tinctoria

Intermediate strain of Japanese Indigo with white flower.

The seed was obtained from Lisa George Fukuda a fellow plant dyer in Guernsey who had it originally from Teresinha Roberts at Wild Colours

Unfortunately this was planted out late in the year (August) so as yet I know little about its habit as there has not been enough time for it to grow to full maturity.

  • Longish leaves
  • White flower
  • Easily damaged by high nitrogen fertilizer.
  • Mid green leaves
  • Quickly bushes out, highly branching.

All three strains were grown on the Natures Rainbow allotment in Hitchin in a chalk soil with a strong application of Fish, Blood and Bone plus some chicken manure pellets.

Persicaria tinctoria

Leaves from all three strains.

Persecaria tinctoria

Rounded leaf Japanese Indigo growing with the Long Leaf strain in the greenhouse. Here they look like two completely different species.

The experiment

After stripping the leaves from the freshly cut indigo stalks, 220g of leaves from each strain were slowly heated from room temperature to 80°C in stainless steel pans with 4 litres of tap water. The pans were stirred at short intervals throughout. Note: the weight of leaves was determined by the amount of the long leaved strain that I could harvest from shoots that had not yet come into full flower as I wished to minimise the effect of flowering on indigo production. The amount of water in the pans was deliberately large as I wished the final colour to be on the pale side as variations in pale colours are easier to distinguish. More water also means the pot is easier to stir before the leaves are cooked.

Heating to 80°C took about 35 minutes. The pans were then taken off the heat and allowed to cool, free standing in the air for 1 hour. (The air temperature was appoximately 20°C).

Persicaria tinctoria

Intermediate Japanese Indigo extraction bath with container of liquor to show gray colour. Photo taken just after pan was removed from the heat.

At this point no difference could be noticed between the different pans. The liquor in each pan being a pale greyish blue in each case.

After one hour the leaves were removed by straining through an old pair of tights into a large plastic bucket. Half a cup of household ammonia was then added to the liquor. Taking care not to breathe in hot fumes, this liquor was poured back and forth from bucket to pan 10 to 15 times to aerate and oxidise the indigo precursor to indigo. The colour of the liquor changed from grey to yellow green, with the round leaved plant giving the darkest colour change and the long leaved plant the least. This is a good indicator of how much indigo is present in each pan.

Once oxidised to indigo, the liquor is now in a stable form and can be left for long periods without any loss of indigo. The reduction vats (indigo dye baths) were set up the following day as follows. The pans were heated to 50°C, one level teaspoon of Spectralite (Thiourea Dioxide) was added to each pan, gently stirred in and left for 30 minutes for the indigo to reduce to its soluble form. Identical weight skeins (26g) of wool were added to the baths at 50°C and left for 20 minutes before removal and oxidation in the air. The dye baths were kept in a hay box to maintain constant temperature during the dyeing.

The results

Japanese Indigo

First results showing a surprising difference in colour obtained

The long-leaved plants (left) were disappointing only producing an ice blue colour. The white-flowered intermediate-leaved plant gave a slightly deeper shade but still pale (centre). The round-leaved plant produced a respectable light blue (right).

The poor results for the long-leaved plants was understandable because of their flowering state, however I was surprised the colour was quite so pale. The good results for the round-leaved plant was a real surprise as I had become convinced these plants would not be the best. Overall the pale colours made me worry that I had not optimized the process and I decided to repeat the experiment for the round-leaved and intermediate-leaved white-flowered plants (I had no more of the long-leaved plant so I could not replicate this one).

On the second run I made one change which was to slow the cooling of the extraction bath after reaching 80°C by placing the pans in hay boxes. For this experiment, using 4 liters of water I was aware that this small amount of liquor would cool quickly, perhaps too quickly? An experiment we conducted some years ago revealed that premature cooling of the extraction bath resulted in a dramatic loss of indigo when processing woad leaves. Two years ago we discovered that leaving the bath at a high temperature for more than one hour also results in a loss of indigo so I have become wary of putting large baths in hay boxes which are capable of maintaining a high temperature for hours.

In this second run the results from the white-flowered intermediate-leaved plant improved but the round-leaved plant still produced the better result (which itself was no better than in the first run).

Skeins of wool dyed with Japanese Indigo

Second run with intermediate white flowered indigo plant compared to rounded leaf plant.

Skeins of wool dyed with Japanese Indigo

Comparison of intermediate white flower strains. The difference between quick and slow cooling of the extraction bath.

Wool dyed with Persicaria tinctoria

No real difference between runs for the Rounded leaf strain.

Discussion

In theory all three plants should have produced broadly similar amounts of indigo. That they did not could have been due to genetic differences but as noted above all three plants were at different stages of development having been planted at different times and the round-leaved strain had possibly adapted to the local soil over the 4/5 or so years I have been growing it. The poor results from the long-leaved plant may have been entirely due to their flowering state. The intermediate-leaved white-flowered strain had only been planted out in late August and may not have had sufficient exposure to the sun to develop much indigo.

The diversity of results shows how critical it is to grow and harvest the plant at the right time. I was certainly concerned that harvesting the plants in October was a risk, as all three varieties were producing flower buds (although only the long-leaved plants were in full flower). Later I extracted a concentrated bath of indigo by making up a large pan crammed full of leaves and only enough water to barely cover the leaves when they were pressed down forcibly. The results were pleasingly strong indicating that the leaves were still fully charged with indigo.

Skein on right dyed with a strong indigo dye bath

Skein on right dyed with a strong indigo dye bath

I will certainly be making strenuous efforts to continue to save the seed from the round leaf strain whatever the reasons for the underperformance of the other two strains!

Confirmation of results

Since this post Leena Riihelä writing in her blog (see Riihivilla) has confirmed that the long or pointed leaf variety of Japanese Indigo does not produce as much indigo as the broad or rounded leaf variety. Leena who also grew three strains of Japanese indigo this year also speculates that the broad leaf (rounded) variety originated in Japan. (The long leaf variety may come from Northern Japan or China). She is also able to confirm that the long leaf variety flowers much earlier. Leena is based in Finland which has such a short growing season that the rounded leaf variety does not have time to produce seed. Leena has a wealth of experience to share about indigo and other natural dyes so please visit her blog and web site. (see below)

Thanks to:

Brian Bond
Leena Riihelä at Riihivilla
Lisa George Fukuda
Pallas Hubler

Indigo dyed wool

The range of blues obtained from the three strains of Japanese indigo.

Madder Red by Robert Chenciner

Looking into Chenciner’s Madder Red

An article by Ashley Walker
© copyright 2017

Madder Red – A history of luxury and trade (2000) by Robert Chenciner
published by Curzon Caucasus World ISBN 0 7007 1259 3

This book is devoted to all aspects of the history of madder from cultivation, through process, economics and use of dye and pigment. The author has collected together in this one reference work the result of many years research.  It is a mine of information. The book is not a light read and the first time I was able to get hold of a copy I only read the chapter on madder cultivation which I found of particular interest. Since obtaining our own copy I have discovered the book contains many additional snippets of information on cultivation and use which compliment our earlier article (see here). My interest, from the point of view of the small scale grower and crafter, covers those aspects of growing and using madder that could be employed on a domestic scale. In the remainder of this article I attempt to extract information of practical use (see comments in Red).

The Madder Plant

The book contains information collected from multiple sources from all over the world but chiefly from the Caucasus and Russia. The focus is mainly on Rubia tinctorum  but other plant sources of red dye are also noted, particularly Rubia peregrina (Wild Madder) which was used quite often when tinctorum was not available. The roots of peregrina contain purpurin and little or no alizarin. Purpurin was valued for producing superior pink and violet shades.

Plant diversity, propagation and seed fertility

In different places madder appears to be adapted to local conditions and taking seed or plant material to grow in other parts of the world often resulted in failure – though this may have been due to inexperience of the new farmers. The book also confirms my own experience that the seed of madder is difficult to germinate and can easily become infertile due to poor storage.

For the home grower this means using the seed as soon as possible (within a year of harvest).

Farmers invariably preferred to sow seeds direct but only the most experienced could do this with success. New farmers preferred to grow the seeds in nurseries and then transplant into the fields when big enough or take rooted shoots from a field being harvested. Transplanting was harder work (and so more expensive) but ensured a greater chance of success.

Crop rotation, maintenance and soil fertility

Maintenance

Six months after planting, the rows of madder plants were “earthed up” (like potatoes) to encourage the plant to put out side shoots (underground stems) and protect the plant from drought in the summer and hard frosts in the winter. This practice is also reported as improving the quality of dyestuff.

For the home grower this seems a sensible activity if you like to grow madder in rows as it would allow the roots to be more easily dug out.

The main maintenance job is reported as weeding, with the most difficult weed being couch grass. I have to agree with this as couch grass has a very similar habit to madder and also forms a mat of underground roots which are extremely difficult to untangle once they get a grip.

Crop rotation and soil fertility

Most of Chenciner’s references to soil fertility indicate that madder harvests (weight of root and quality of dyestuff) will decrease over several years if grown in the same soil continuously – even if the soil is well fertilised with manure. A figure of approximately 6 to 12 years is mentioned as the maximum length of time that madder could be grown economically in the same field. After this time the land had to be left fallow or rotated for several years (4 to 12) before any further madder crops could be grown. Typical rotational crops were rapeseed, beans, wheat, hemp, turnips, beet, potatoes and cabbage.

Several references are made to observations that madder grew best on virgin ground which is much the same as any other crop, but the failure of manure to restore fertility suggests a depletion of some micro-nutrient not present in manure. The only suggested method of restoring fertility quickly was to add “natron” and common salt. Natron is a mixture of hydrated sodium carbonate salts and other salts found in dried up lakes.

For the home grower it may be possible to substitute common washing soda for natron but I would not recommend doing so without careful experiment first to find out how much to apply. Washing soda is a powerful alkali and sprinkling it on soil could do serious damage.

Adding small quantities of sea salt (35g per m2 about twice a year) may be a better solution but be careful not to overdo it. Rock dust may also do the job.

How long to grow the plant before harvest?

Throughout its history this subject has been the source of much discussion and the author comes to two conclusions:

  1. Older roots (3 to 5 years) produce the best quality dyestuff.
  2. Economically it was best to harvest after 1 to 2 years.

As you can imagine 3+ years is a long time to wait before being paid, particularly if as an “adventurer farmer” you had to pay rent on the land/accommodation and feed a family during this time. Most successful ventures appear to have been run by established land owners who had minimal overheads and additional sources of income. Some farmers did practice a form of partial harvest where a trench was dug beside the row of madder plants. Roots found in the trench were harvested without killing the main plants which continued to grow for a further year or two.

This practice makes home growing of madder considerably less of a wait though the final harvest may be reduced.

Harvest and processing of madder root

Steaming

The first procedure after digging the roots was to steam them, a practice carried out in the field by a team of specialists. All sources are clear that this process increases the amount of dyestuff in the root and after about 4 to 5 hours the roots would turn from yellow orange to a strong red. A hole was dug in the ground and a fire lit. When the surrounding soil had become baking hot, madder roots were piled on top and then the whole heap was covered in damp cloth or similar material to keep the hot air in.

Although we have never tried this I see no reason why it would not be possible to do this at home using standard vegetable steamers. The exact method will need to be worked out by experiment.

Washing

There are very few reports of root washing in the book and when it is mentioned it is not recommended for fear of loss of dyestuff. I would guess that the growers wanted to keep even the poor quality brown dyes found in the thin skins. Any soil clinging to the roots would just add to the weight of the final product, so more profit!

Drying

In the Netherlands and Britain this was done in specially built heated drying houses as the climate here was not hot enough to dry outside. Even in the Caucasus and other hot dry areas most growers preferred to dry in the shade rather than direct sun. This slow drying is reported as another essential process to further increase the amount of dyestuff in the roots. Roots were often stored for one or more years to allow them to mature before being pounded into a fine power or “krap”. The roots had to be brittle dry before pounding otherwise the root would stick into a hard cake.

For the home grower the important features of this drying process is the temperature and the length of time. The recommended temperature was between 20°C and 30+°C so drying in an airing cupboard would probably work well with storage in a warm dry place after the roots have dried out completely.

Fermentation

Fermentation was sometimes done before pounding, sometimes afterwards and involved placing the root material into a vessel with water for a short time (a few days) during which time the sugars in the root were fermented out. Removing the sugar was important as later fermentation in the dye bath interferes with the dyeing process.

From the home dyer’s point of view this is not so important unless you make your madder dye bath a day or two before using it.

Pounding

When the madder industry was in full swing the roots were pounded in large horse-powered or water-powered mills and the resulting powder or krap was sorted into a variety of grades. The main problem besetting the root processors was separating out the “tough” outer skin which contains the brown dyes that would dull the final dyed product from the inner “parenchyma” part of the root which contained most of the dyestuff. Exactly how this was done is not explained but logically krap was probably sieved into coarse and fine fractions and the first powder produced after partial pounding would have presumably contained most of the bark.

For the craft dyer pounding is not really an option. It may be possible to grind the root in coffee bean grinders but only if you are prepared to say goodbye to the grinder. The metal blades in such grinders could be a problem if they become rusty and end up adding iron to the dyestuff which would sadden the colour. Chenciner reports that some pounding mills used wooden hammers with ends strapped in metal (possibly iron) so the danger cannot be catastrophic.

There has been some confusion amongst today’s craft dyers about exactly which part of the root contains the dyestuff. Nowhere in the book does the author note the differentiation of root into ‘true roots’ and ‘underground stems’ or rhizomes, although some of the quotes from historical documents do allude to this. The root is invariably described as having a thick tough bark but this is clearly an impression formed by looking at the dried root. The skin of fresh root is very thin and can be easily scrubbed away on an individual root but this is probably not possible on a large scale without losing a lot of the underlying dyestuff. The position of the dyestuff in the root is usually described as being just above the woody cortex, but again this is probably a description of a dried root where the soft fleshy outer material has shrunk to a thin layer of concentrated dye bearing material just covering the woody cortex.

Rubia tinctorumIn the shrinking process, the outer skin wrinkles up and appears to become quite thick.

In theory it would be possible to hand wash fresh roots then pound the roots in a strong pan until the woody cores could be removed and the remainder left to dry. This would be very labour intensive however and the inner pith from root stems (which also contains dyestuff) would remain in the removed woody material.

During a Turkey Red workshop run by Debbie Bamford (The Mulberry Dyer) at the 2013 Spinners Weavers and Dyers Guild summer school an experiment was done to try and separate the outer part of the root from the inner cortex and test the resulting material for dye strength and colour. Most of the commercially obtained dried root was actually root stem with the characteristic central dot of red pith. The outer layer of bark and inner dye-rich material was shaved off with potato peelers, down to the pale woody cortex. It was not possible to remove all the dark material. Equal weights of shavings and inner cortex were then used in identical dye baths. The shavings gave the darkest red with little if any dulling due to the presence of outer bark.
root-experiment

For the home dyer wanting the brightest reds the easiest way to remove the brown dyestuffs from the bark is to set up the dye bath using your preferred recipes and after a first heating of root pour off the liquor and replace with fresh water. (See Jenny Dean)

Refining the powdered madder root

When the Madder industry expanded in the 18th and 19th centuries it was not long before competitive manufacturers began to invent new mechanised ways of refining the krap to increase its quality. The first breakthrough using a complex chemical treatment resulted in “garancine” which was later purified even further into “flowers of madder” which was almost pure “alizarin” (the main dye chemical in madder root). These refined products enabled the dyer to dye product quickly, easily and reliably.  Krap became an inferior grade product and perhaps contributed to its entry into the dictionary as the word “crap” meaning rubbish.

For the home dyer, refined madder root products are still produced and sold as madder extracts but these are expensive and I think less exciting than growing your own or making do with chopped root or krap. Home refining is possible (see Michel Garcia) but you do need some specialist laboratory equipment.

Economics

Chenciner is particularly interested in the economics of madder growing, processing and use. As a very high value product, madder growing attracted “adventurer farmers”. It is hard today to imagine farmers being put into the same class as gold prospectors but the potential returns on investment were such that many amateurs were drawn in. Of course many of these inexperienced adventurers were doomed to failure. What seemed like a shortcut to riches and fortune soon turned into a nightmare as old seeds sold by unscrupulous traders failed to germinate or the crop simply failed to grow well or any number of other disasters befell the hapless farmer.

Recipes from History

Contained in the text are numerous recipes for the processing of madder and dyeing of various fibres and textiles. These recipes are often quoted without interpretation into modern terminology so often remain obscure. However, they do offer a fascinating window into historical techniques and a platform for modern attempts to duplicate them.

Historical texts referred to:

The Leyden and Stockholm papyri (a Greek/Egyptian document written around 300AD which contains many recipes for the dyeing of fibre some of which use madder), e.g. :-

  1. Dyeing in Rose Colour  Rose colour is dyed in the following way. Smear the rolls of wool with ashes, untie them, and wash the wool in the liquid from potter’s clay. Rinse it out and mordant it as previously described. Rinse it out in salt water after mordanting and use rain water (which is so) warm that you cannot put your hand in it. Then take for each mina of wool a quarter of a mina of roasted and finely pulverized madder and a quarter of a choenix of bean meat. Mix these together by the addition of white oil, pour it into the kettle and stir up. Put the wool in the kettle and again stir incessantly so that it becomes uniform. When it appears to you to have absorbed the dye liquor, however, brighten it by means of alum, rinse it out again in salt water, and dry it in the shade with protection from smoke.

The Plictho of Gionaventura Rosetti: Instructions in the Art of the Dyers Which Teaches the Dyeing of Woolen Cloths, Linens, Cottons, And Silk by the Great Art As Well as by the Common (1548)

RED Madder wool-spinning-small

Rubia tinctorum

Growing Madder

An article by Ashley Walker
© copyright 2017

Common Madder (Rubia tinctorum) is an excellent source of red dye. It is indigenous to Southern Europe, Middle East, Central Asia and North Africa but has many close relatives (in the genus Rubia) around the world.

Rubia tinctorum

Young madder plant

Propagation, Care and Maintenance

As a herbaceous perennial, Common Madder dies all the way back to the soil at the end of every year. This means that madder beds can be mulched over the winter to suppress weeds and protect the soil from nutrient loss. Mulching with well-rotted manure or other soil improvers will have the added benefit of fertilising the soil.

Rubia tinctorum

Shoots of madder in the early spring surrounded by the dead stems of last year’s growth

Madder shoots appear in March and will withstand mild frosts. They grow into a mass of long clambering stems which need support to grow above a foot or two in height. Madder will tolerate coastal conditions of wind and salt and is highly resistant to pests and diseases. Seedlings will benefit from protection from slugs, but the shoots of mature plants need no protection. Growth can always be improved with a little fertiliser and watering in hot dry weather but we generally leave our madder to fend for itself and it still gets good harvests. The green part of the plant contains very little dye stuff but was used as animal fodder and reportedly would turn their bones red over time.

Growing Common Madder requires considerable investment from the dye plant gardener. From seedling or cutting it takes three to four years before the roots have swelled to provide a satisfactory harvest. Time is not the only consideration either. The plant is highly invasive and if neglected it will spread to the rest of your garden. The plant’s main method of propagation is the underground stem which grows horizontally under the surface and pops up one to three feet away. If you are a diligent (and ruthless) gardener you can keep on top of it by pulling up the shoots every time they reappear. Our approach is to set aside part of our vegetable allotment for madder. We remove stray roots as and when we dig the vegetable beds over. In ten years we have only once had to take more drastic measures when the madder was heading for the neighbour’s allotment. Madder roots and shoots are relatively thick which makes them easy to remove when digging; keeping the plant under control is far easier than dealing with perennial weeds like bindweed and couch grass. If you have no ‘out of the way’ space suitable for madder and you maintain an ornamental garden, madder can be grown in a large raised bed with deep walls to prevent the underground stems from escaping or, failing that, a very large planter. Setting up a separate raised bed each year for four years would allow you to harvest madder every year. The larger the container or raised bed the better. As with all container gardening, the plants will need extra attention to watering and feeding compared to madder grown in open ground.

Rubia tinctorum

Green berries of Common Madder

Rubia tinctorum

Madder berries turn from green through red to black. Although the black berries produce a wonderful red juice it does not appear to be a useful dye.

Madder also propagates itself by seed. The seed of Cleavers (a close relative) is covered in tiny hooks which attach to passing animals. With Common and Wild Madder the large seeds are surrounded by a juicy black berry which is eaten and spread by birds. Madder seed once dried is notoriously difficult to germinate. Many sources suggest that it will self-seed readily in some countries but we have never come across a seedling in our allotment. All of our madder beds were derived from a single seed we managed to germinate many years ago. So if you know someone who is already growing madder ask them for a root cutting from the underground stems in the spring and you may save yourself a lot of time.

Note: If growing from seed I previously recommended using advice from a scientific paper [1] which had found that soaking the seeds in very hot water for a few minutes would help break the seeds dormancy but having tried it ourselves I can categorically withdraw this advice. DO NOT DO IT! All I managed to do was kill the seeds! I will be writing up the results of this experiment soon.

With its scrambling habit and close resemblance to cleavers, most people would not judge Common Madder an attractive garden plant. However, if weeds are kept at bay, large beds of madder produce beautiful clouds of tiny yellow star-shaped flowers in July/August and glossy black berries in October. Providing support for it to clamber over also improves its attractiveness.

Rubia tinctorum

Rubia tinctorumRubia tinctorum

Rubia tinctorum

Harvesting Madder Root

Rubia tinctorum

Underground stems (Rhizomes) and true roots

There are two main types of root: bulbous true roots and straighter underground stems or rhizomes.  Once established, the adventurous rhizomes soon start to swell and take on some of the characteristics of real roots. They begin to produce and store the various substances that bear pigment. Both true roots and new plant shoots grow from these rhizomes. The bulbous true roots are the most prized by dyers but three year old underground stems can be just as good so do not discard them.

Rubria tinctorium

The bright orange shoots are new growth stems.

Rubia tinctorum

Network of underground stems just under the surface.

Rubia tinctorum

Cut underground stem, note the orange woody ring with red center of pith.

Rubia tinctorum

Cut root with thin woody centre

Having to dig up the root is often cited as a barrier to growing Madder, particularly if the soil in your garden has a lot of clay but there are many ways to make the task easier. If you do have heavy soil invest in several bags of soil improver and a few bags of sand and dig in well before planting. If that sounds too strenuous, create a “no dig” bed and spread over it a very thick layer (at least one foot or thirty centimeters) of a mixture of manure, soil improver and sand. Top this up in the second or third winter. It is true that madder roots will go very deep (several feet) into the ground but there is no need to dig down that far as most of the roots, including the largest ones, are usually near the surface.

Rubia tinctorum

Root stems and rhizomes before and after washing. With a little gentle brushing the outer surface of bark (which contains brown dyes) can be removed to reveal the orange flesh of the root. The difference between root stem or rhizome and true roots is seen here . Root stems are invariably straight and have a woody ring with red pith centres. True roots are twisty and have a thin woody centre.

Rubia tinctorum

Soil type is not important to the health of the plant but growing madder in an alkaline soil stimulates the production of the red dye stuff. We are fortunate to have a light chalk soil in our garden which is already quite alkaline. For acid soils an application of lime will improve the dye yield.

The general consensus is that the best time to dig Madder in Northern Europe is late Autumn, after the roots have been replenished by a full season’s growth. The worst time to harvest is Spring when all the nutrients are coming out of the roots and going into new growth. However, we have harvested at all times of the year and found that the results are  similar so don’t be too constrained by the literature. Of more import is what you do with the roots after harvest.

Rubia tinctorum

Mature madder root

Rubia tinctorum

Once removed the outer bark reveals the translucent orange flesh. The central woody core can be seen here through the root.

Rubia tinctoria

Washing the roots with a jet of water

Root Processing

First they need to be washed to remove loose soil. This can be done with a hose connected to the mains and the spray head set to a narrow jet.

We leave the wet roots to drip dry outside in net wash bags and then move them to a warm, dry place out of direct sunlight where they will get plenty of air circulating around them. It takes around one to two months to fully dry the roots, when they can be snapped by hand or chopped up for storage in air tight containers or paper bags in a dry place. Slow drying followed by long storage allows more of the precursor substances in the root to be converted into alizarin which is the substance that gives the classic pink/red. The root is admittedly easier to chop when fresh but then much more difficult to dry unless you have access to a herb dryer.

The clean roots can be used immediately but remember that most dye recipes specify quantities for dry root. Our experiments show that drying reduces the weight by a factor of six. So rather than 50% weight of goods you will need 3 times the weight of goods in madder. Fresh root is also useful for dyeing cloth in eco-bundles.

Rubia tinctorum

The dried root is chopped up for final storage.

Although it involves more work and considerable patience, we much prefer to dry the roots and keep them for a year or so before use. Indeed we think that along with our chalky soil and hard water, this may help to explain our success in achieving very good reds from our home grown madder.

Other red giving plants for your dye garden

It could be argued that Common Madder, being so easy to grow and yielding a great deal of pigment is the only dye plant in the UK worth growing for reds. However why should we limit our plant dye and botanical knowledge in this way? There are a number of related plants which have played an important historical role where soils are not well suited to Common Madder. While it is against the law to uproot any wild plants, many of these can be easily grown from seed and some are available from wildflower nurseries. Examples include Field Madder (Sherardia arvensis), Wild Madder (Rubia peregrina), Lady’s Bedstraw (Galium verum) and Dyer’s Woodruff (Asperula tinctoria). Wild Madder appears very similar to Common Madder but is evergreen and grows wild in South West England and South Wales. Lady’s Bedstraw is a lovely perennial wild flower with dense clouds of yellow flowers in July and August and surely deserves a place in the dye garden?

Rubia Peregrina

Wild Madder (Rubia peregrina) found growing in a hedgerow near Brixham, Devon 2nd Jan 2017. Photo by Brian Bond.

It is said in the literature that these relatives of madder do not provide as much colour as Common Madder, primarily because the plants are harder to harvest and the roots are thinner. Even the common weed, Cleavers or Goosegrass (Galium aparine) is said to contain similar pigments to Common Madder although its thin roots are unlikely to yield enough for true reds.

A further article based on the book “Madder Red” by Robert Chenciner will be posted later in the spring when I’ll be looking at the history of growing madder and its lessons for the craft grower.

Bibliography

Ecotone Threads (another really good blog post on growing Madder by Kori Hargreaves in California).

Chenciner, R. (2000) Madder Red: A history of luxury and trade Curzon, Caucasus World

Sandberg, G. (1996) The Red Dyes: Cochineal, Madder and Murex Purple, Lark Books

Cardon, D. (2007) Natural Dyes, Sources, Tradition, Technology and Science, Archetype Publications London

[1] Sadigheh, S. et al (2009), Study Methods of Dormancy Breaking and Germination of Common Madder (Rubia tinctorum L. ) Seed in Laboratory Conditions, Botany Research International, 2 (1): 07-10  See http://www.idosi.org/bri/2(1)09/2.pdf

Isatis tinctoria

Growing Woad

An article by Ashley Walker
© copyright 2016

Woad (Isatis tinctoria) is a naturalised hardy biennial member of the Brassicaceae or cabbage family and was probably introduced into the UK from Europe. There are no close relatives in the UK but there is a similar plant from China called Chinese Woad (Isatis indigotica) which is primarily is grown as a medicinal plant but is also used as a source of indigo. Various web sources including Wikipedia assert that indigotica and tinctoria are botanically indistinguishable. I have recently obtained some Chinese Woad seeds from a German company (Rühlemann’s) so intend to find out the truth of the matter next year. Woad will grow up to four feet high and here in Hertfordshire it flowers in May. The flowers, like so many dye plants, are yellow and make a terrific show in spring.

Unfortunately Woad is classified as a noxious weed in many western states of the US so if you live in one of these states please find out what the restrictions are before you even consider growing it. Here in the UK although it has naturalized and self seeds readily it is not invasive and only tends to grow in disturbed ground. Seeing it in the wild is a rarity. I have been reading about its invasiveness in the US and I now understand that it can invade wild areas of the West with ease probably because these areas are similar in habitat to its native eastern European and Asian plains. It is now classified as a noxious weed in the following states Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. I have not found any reports of problems in the East of the US so would appreciate it if anyone who has any knowledge of this could let me know. Many thanks.
More information can be obtained from this short online document here. For really comprehensive information see here.

Isatis tinctoria seeds

The flat winged seeds of woad contain more than one seed

Woad generally produces masses of large seed “pods or cases” that are only viable for one year. These take a few months to mature and start falling or being blown to the ground by August. The seeds will then start to germinate as soon as the weather becomes wet (inhibitory chemicals in the seed case are washed away by rain). By late October/November new plants will have grown to a substantial size (big enough to harvest). Many seeds will not germinate until the following spring and a few of these will grow and flower in the same year. Those that do, will probably return to a rosette stage towards the end of summer which leads to the unusual sight of rosettes growing at the top of a long stem. Some second year plants will also survive flowering and also return to producing rosettes at the end of summer. These second year rosettes also produce indigo in the leaves.

Isatis tinctoria

Left a smooth edged leaf rosette and right a toothed leaf plant

Isatis tinctoria

 

 

 

 

 

 

 

 

Isatis tinctoria

A second year plant that survived its first summer and has returned to the rosette stage (sometimes called a “crown rosette”)

There appears to be a great deal of phenotypic variation between Woad plants. There are big differences in leaf colour ranging from blue/green to pale yellow/green and leaf shape from toothed to smooth-edged. Because of this variability, Woad seedlings can be easily mistaken for weeds at first, especially if they have popped up in unexpected places. However, all Woad plants have a highly distinctive aroma, once smelt never forgotten! It seems likely that plants also differ in the amount of indigo they contain, so there is probably scope for plant breeders to improve the stock.

Propagation

Isatis tinctoria

The long white tap root of a two to three month old young Woad seedling.

Isatis tinctoria

Directly sown Woad bed. Really this bed could have used some thinning out, but it demonstrates that a dense planting will crowd out weeds very effectively.

Woad seeds are only viable for one year so make sure that your seed is fresh. If you buy commercially available seeds there will only be a few tens of seeds in the packet I don’t recommend that you risk them by sowing direct. Sow well away from slugs and snails indoors or outdoors in early April. There is no need to heat the trays. Each winged seed case actually contains more than one seed and so can produce more than one seedling. The plants will grow quickly. Plant them out on a warm day in early May. There’s no need to wait until the last frost as they are hardy.

I have only ever needed to buy Woad seeds once. The plants produce thousands of seeds which will spread around the garden and germinate in mid to late summer. I collect a carrier bag full on a dry sunny day in late summer when the seeds have fully matured. They store well if kept dry. I sow them liberally onto a prepared bed the following April, where they germinate readily and then may need thinning out.

At the beginning, to avoid having to buy the seeds two years running, keep a few seeds to plant in October. Depending on conditions, if you are lucky some of these late sown plants will stay in the rosette stage long enough to providing a useful crop for dyeing in the summer of your second year.

The young seedlings produce long tap roots that can penetrate deep into the ground, so the plants rarely suffer from drought. However watering regularly will encourage growth. The larger the plants the more water they need.

Care and Attention

Isatis tinctoria

Self-seeded Woad

Woad, like Japanese Indigo needs copious quantities of fertiliser to get a good crop. Animal manure is excellent if you can get it. This is best dug into the top few inches of soil before sowing or planting out and will last the whole season. Woad generally does not suffer from many pests and only a few diseases. As a cabbage family plant it may suffer from club root when grown in acid soils, but I have not heard any reports to that effect. When grown densely it does attract the attention of a few species of slug and snail but these seldom threaten the plant’s success so there is little need to take protective action.

Harvest

The amount of indigo in Woad leaves varies according to the weather and the plant’s developmental stage. The plant produces more indigo when the weather is hot and sunny but once the plant has started to produce flower stems in early Spring the amount of indigo in the leaves rapidly diminishes, falling to zero when the plant is in full flower. For this reason Woad is invariably harvested in the summer of its first year while still in a rosette stage. The leaves at this stage are thick, fleshy and give off Woad’s characteristic smell when bruised. The smell is not pleasant but it has such good associations for me that now I have come love it. It is sometimes possible to trick the plants into returning to their rosette stage by cutting the flower stalks before the seeds form. Once harvested, the leaves need to be used the same day. When Woad was grown commercially in the UK the leaves were crushed in a mill and the resulting mass shaped into balls which were then set aside to dry. Woad stored in this way loses some of its indigo.

Further information on Woad and Woad products can be obtained from:

The Woad Centre This is a web site by Ian Howard from Woad Inc the UK’s only commercial grower and processor of indigo from Woad.
A journey into the Blue Article by D.J.Hill
Bleu de Lectoure A Toulouse based company which also grows and produces indigo from Woad.
Isatis tinctoria

 

Isatis tinctoria

Magnificent Woad

Isatis tinctoria

Cota tinctoria

Growing Dyers Chamomile

An article by Ashley Walker
© copyright 2016

Dyer’s Chamomile or Golden Marguerite (Cota tinctoria also known as Anthemis tinctoria) is described as a hardy but weak perennial because it usually dies in the late summer of its second year. It is a sprawling daisy-type plant, growing from one to two feet high. The leaves are feathery and often look blue-green. It originates from Southern, Eastern and Central Europe. The fragrant flowers last a long time (two to three weeks) and are not bleached by direct sunlight. Incidentally this is a good way of assessing just how light fast the dye from flowers can be.

There are numerous sub-species, hybrids and garden varieties e.g.
Grallagh Gold”, A yellow orange hybrid of Cota tinctoria and Cota sancti-johannis
Kelwayii”, Deep yellow petals
Charme”, Yellow petals
E.C Buxton”, Pale yellow petals
Wargrave variety”, Pale yellow petals
Sauce Hollandaise”, A hybrid of Cota Tinctoria and Cota punctata. White with yellow centre
Suzanna Mitchell”. White petals

I have only grown the unnamed variety of Dyer’s Chamomile (sourced over 8 years ago from Suffolk Herbs, now King’s Seeds), so I cannot comment on the quantity or quality of dyestuff produced by these named varieties. This  is an experiment waiting to be done! My guess is that probably all produce some dye and that “Kelwayii” may be the best for the dye garden as it has completely yellow, large flowers and will self-seed if the conditions are right.

Propagation

Cota or Anthemis tinctoria

Newly planted Dyer’s Chamomile seedlings

Cota or Anthemis tinctoria

Dense planting of Dyer’s Chamomile seedlings

Cota or Anthemis tinctoria

Dyer’s Chamomile coming into flower

I usually grow Dyer’s Chamomile from seed which I saved from the previous year’s flowers. Its seeds have a good shelf life of three or more years if kept in dry cool storage. The small seeds should be sown thinly in seed trays from early April. They germinate easily and can be planted out when large enough to handle. The plants are hardy so can be planted before the last frost. Cuttings can be taken and will root readily – indeed this is the only way to propagate the hybrid varieties. If you have excess seedlings don’t discard them. If regularly watered, they can be kept for at least a year without flowering. Restricting their roots arrests their development but does not prevent them from springing into action when planted out. There are few plants that can be mistreated in this way, but chard is another plant with the same properties.

Dyer’s Chamomile will also self-seed but the tiny seedlings usually get eaten by slugs. After growing the plant for several years now, I notice there are an increasing number of self-seeded plants in the garden.

Cota Tinctoria

Dyer’s Chamomile in full flower

Pests and maintenance

For a good display, the seedlings should be planted closely (about six to eight inches apart) in a mass or as a border around a vegetable or flower bed. Close planting will also help to keep the weeds at bay. The plants will grow in all types of soil including poor soils low in nutrients. The plants benefit from some fertiliser so it is probably best to crop rotate, growing as a second crop after heavily fertilised Woad or Japanese Indigo. My seedlings need protection against slugs and snails. These pests can easily eat a plant faster than it can grow, with a tendency to munch on a particular plant until it is completely eaten, while nearby plants may remain untouched. I use organically approved slug pellets until the plants are big enough to fend for themselves. This can take quite some time (two to three months). When in full flower the slugs often climb up the stems and chew through the flower stalks, but the damage is usually small. The plants can withstand drought but regular watering in hot dry weather will ensure rapid growth and a good harvest.

The first year plants come into bloom from August and flower until late September. Towards the end of Autumn the plants start to look straggly and untidy. If the plants are cut back close to the ground before the flowering finishes, in September, they will produce some new growth before the growing season ends, which helps the plants to overwinter. In the second year the plants will flower early, from June to August, In both the first and the second flowering seasons, regular picking of flower heads will encourage new flowers to bud.

Harvest and Storage

Cota or Anthemis tinctoria

The top flower is mature and full size, nearly all the small florets are open The smaller flower, below, has not long been open.

dyers-chamomile-harvest2

Harvested flowers

Cota or Anthemis tinctoria

Storage Jars of Dried flowers

 

 

 

We harvest the flowers every two to three weeks. When the flowers first open they are quite small but increase in size and weight, so we try to only pick the more mature flowers. Once harvested, we dry them in a herb dryer and keep them in storage jars. Drying usually takes several hours and then it is best to leave the dryer switched off overnight before giving it an additional hour the next day. If the flowers are stored even very slightly damp they can become mouldy. It usually takes two or more harvests to fill one large storage jar, which provides enough dyestuff for a 10 litre dye bath. The stems and leaves of the plant also provide some dyestuff, so we sometimes cut the plants back at the end of the season and dry these too.
A word of warning about storing Chamomile flowers in poorly sealed containers. The mature flower heads contain a lot of nutritious seed material. One year we stored mature dry plants in paper sacks inside snap-top plastic storage boxes. But this attracted the attention of “Pantry” or “Larder” beetles which caused an infestation! We now only store dried flowers in fully airtight containers.

Seed Saving

Cota or Anthemis tinctoria

Old flower heads can be picked and dried for seed. These flower heads are not yet too old to be picked for dye.

Cota or Anthemis tinctoria

Seeds with drawing pin for scale

Seeds can be obtained from the old flower heads which have lost their colour and petals. These can be picked and allowed to dry in the sun or left on the plants until dry. The second year plants, having flowered first, will have ripe seeds by August. If you are growing a named variety it is likely that over a few years of seed saving the plants will revert to the normal wild type, so may not be as decorative as the original plants but will still produce plenty of dyestuff. Separating out the seeds from the chaff is done by rubbing the dried flower heads to release the seed and then shaking in a tray while blowing the chaff gently out.
The seeds, though small, will collect at the bottom of the tray.
If you are growing several varieties of chamomile be aware that the plants will readily cross-pollinate. If you want to keep the variety true it’s best to keep them in very well separated beds.

Cota Tinctoria

Dyer’s Chamomile in a cottage-garden style planting with Vipers Bugloss, Lavender and Feverfew.

Cota or Anthemis Tinctoria

Cota or Anthemis tinctoria

Dyer’s Chamomile is not a strong bee or butterfly plant and only attracts the occasional solitary bee and flies. All the above are flies.

Cota or Anthemis tinctoria

Dyer’s Chamomile flowers on Chamomile dyed fleece