Yellow pea like flowers of Genista blossom

Growing Dyers Greenweed (Genista tinctoria)

By Ashley Walker
Copyright 17th February 2020

Dyers broom, Dyer’s whin and Woadwaxen

Dyers Greenweed is a member of the Fabaceae or legume family. It is a typical shrubby broom native to the UK, growing in open pasture and heathland. It is a source of an excellent light fast lemon yellow dye similar to Weld. As its name suggests it was used with indigo (from Woad) to dye textiles various shades of green.

Horticulture

Like some other native dye plants, Greenweed has declined with the rise of modern agriculture so you are less likely to be able to forage for it. It mostly grows in the West and South of England and appears to prefer slightly acidic loamy clay soils though it will grow in alkaline soils if treated well. It can grow to a height of 1 to 2m and forms a bush, usually growing from a single base stem. There are dwarf varieties and a dwarf subspecies Genista littoralis. It is extremely hardy (surviving temperatures as low as -35ºC) so it should be possible to grow it in the far North. It loses its leaves in the winter and this maybe the reason it’s able to stand the sub-zero temperatures. It does not like being waterlogged but struggles in dry soils too when it needs to be watered occasionally during hot summers.

Dyers Greenweed bush growing in the author’s back garden.

Propagation

The seedpods of Greenweed turn black in late summer and on hot days burst apart scattering the  small pea shaped brown seed.

to show the seeds and seed pods of the plant

Seeds and pods of Dyers Greenweed

These may germinate in the Autumn or stay in the soil and germinate in the following spring. When I first tried to grow the plant from seed I followed the instructions to plant in the Autumn. Although some of the seeds germinated I found that the seedlings died during the winter. so I changed my strategy to planting in Spring which works very well and allows the seedlings to grow large enough during the first year to get through winter without problem.

Start seeds off indoors in modules or seed trays from March to April and plant out in June in a sunny position.

to show what a young seedling looks like

This very young Dyers Greenweed has self seeded but is in danger of being eaten by slugs.

The plants will grow large, so give them plenty of space and plant about a metre apart. They can be grown as a hedge in which case plant closer (say 20 to 25cm). The seedlings are very prone to slug and snail attack, so sowing the seed outdoors is very risky without protection. Cuttings can also be taken. Cut the woody 1 to 2 year old stems in Spring or Summer and just stick them into the soil. Only about 10 to 50% will take so plant more than you need. They will need watering regularly during the summer as they take a month or two to root.

Pests and diseases

shows red ladybird eating aphid pests

Ladybird to the rescue

Aphid on young shoot of Dyers Greenweed

Apart from slug and snail attack when young, the next big problem is aphids, which attack the young shoots in early Summer just when you want to be picking them for dye. The damage can be extensive and I sometimes have to resort to spraying them off with a jet of water from the hosepipe. Ladybird and hoverfly larvae usually get the aphid under control by mid to late Summer and the plants will recover enough to flower. There appears to be quite a bit of natural variation amongst plants with some consistently being attacked and others being generally free of the bugs. So if you find you have a resistant plant don’t hesitate to take cuttings from it.

Deer and other large herbivores also like to eat Greenweed.

Maintenance

The young shoots are best for dyeing. As the plant gets older it produces fewer shoots so the bush needs to be pruned or cut back at least once a year to encourage this new growth. In earlier times when the plant was grown as a source of dye it was typically harvested in the second year when the whole plant was cut down. During the early Spring/Summer take the first harvest of young shoots then cut back in August to get a second growth and harvest. Growing this plant as a low hedge is ideal.

Dyers Greenweed will regrow quickley after being cut back and produce lots of new shoots.

As a member of the legume family, Greenweed is capable of fixing nitrogen in its root nodules. As a result the plant does not need much, if any fertilizer and can grow on quite poor soils. Don’t plant Greenweed in your most fertile bed, so choose instead any bit of scrappy ground that gets full sun. Greenweed will not grow in heavy shade. Against a South facing wall or fence would be ideal. To help keep weeds down after planting you can add some thick mulch around the stems. Water if the soil becomes very dry.

Cultivars

Greenweed is grown as a decorative garden plant for its bright display of yellow blossom in mid to late Summer. If you grow several plants from seed they will probably have slightly different flowering times but if you buy a commercial cultivar each plant will flower at the same time. Commercial cultivars may also be less able to cope with strong pruning and are usually a lot smaller than the wild plant. Three cultivars of note are:

  • Royal Gold – 0.5 to 1m
  • Humifusa – dwarf variety
  • Flore Pleno – dwarf variety

Dyeing

The leaves and young shoots are treated much like Weld except if the stems are woody strip the leaves first. Boiling water is poured on the cut shoots and left for an hour or so to extract the dye. Fermenting the young shoots can also have excellent results. A small amount of alkali (lime water or a drop of ammonia) will bring out the yellow. Dye your textiles in the resulting extract at around 70ºC. This dye is excellent for silk. If dyeing green with indigo a slightly better result will be obtained if you dye indigo first and then over-dye with  Greenweed. The young shoots can be dried for storage and later use.

Silk and Cotton dyed with Dyers Greenweed

Japanese Indigo seedlings growing after dormancy is broken

Japanese Indigo and seed dormancy

By Ashley Walker
Copyright 14th February 2020

Persicaria tinctoria seed dormancy

Don’t throw out your old Japanese Indigo seed just yet.

Strange the things you think about when you are trying to get to sleep. For a week or two now I have noticed some germination activity going on in an old seed tray I moved outdoors at the end of last year. A few days ago (8th Feb) I took a closer look and realised that the seedlings were Japanese Indigo, so I’ve been thinking about this ever since.

The weather here has been very mild since before Christmas, with only a few night time frosts. During the day it’s been warm enough for Japanese Indigo to germinate but how has this happened? Japanese Indigo seeds only stay fertile for about a year, unless you freeze them, right? Well, clearly not, as my seedlings testify. I moved the seed tray indoors and yet more germinations. What is going on?

Although the label on the tray is long missing, I believe that this is a tray of seeds planted during late summer (September) of 2019. I wanted to see how old seeds could and still germinate. I admit my documentation was poor, but when it comes to plants my memory is quite good (more than can be said for my ability to remember anyone’s birthday). Germinations at the time were very poor. Only a handful of plants germinated and eventually I decided there would be no more so moved the tray outside. Outside, the tray has been exposed to all weathers including some hard frosts. Moss and even a Common Rush (Juncus effuses) had grown during the late Autumn and winter. But in all this time the seeds (from 2018) were not dead, but dormant.

Newly germinated Japanese Indigo seedlings growing in moss covered seed tray.

Seed dormancy is a fascinating subject as plants use all sorts of strategies. Some seeds are dormant from the moment they become ripe and need a period of vernalisation or their tough seed coats need to be scarified i.e. damaged before germination. Some seeds will stay viable for decades and others only last a year. I had thought that Japanese Indigo fell into the latter category, as germination rates steadily decline from age 6 months onwards. At 12 months of age few if any seeds will germinate even when sown in good conditions with warmth, light and moisture.

Persicaria tinctoria seed

Japanese Indigo seed.

I asked myself a question. What happens to an annual plant whose seed only survives a year, when there is a serious drought lasting for months? The plant dies out of course. But thinking about it, that’s crazy – no plant would use such a strategy unless it had evolved in a world where there were never droughts or forest fires etc. Japanese Indigo seed with its hard shiny black protective coat actually looks like it’s designed to last a considerable time.

I have a distant background in plant biology and this is what I think is going on:-

Fresh seed readily germinates. But if the environment is harsh and the seed is prevented from germinating, dormancy-inducing chemicals slowly accumulate within the seed. If the seed is exposed to soil bacteria and moisture the protective seed coat slowly breaks down until dormancy is broken. Alternatively the seeds might need to be vernalised to break dormancy. My seed tray was exposed to low temperatures and frost which may have done the job too. As soon as the conditions are suitable the seed then germinates.

So how can the small grower take advantage of this new finding? At the current time I do not know. You can certainly try sowing old seed into trays and leaving them outside during the winter. But, until I know exactly what mechanism was involved (scarification of the seed coat or vernalisation) I cannot say with any confidence how you can break dormancy quickly. More experimentation is needed.

If anyone out there has any further information I’d love to hear it.

Seedlings of Japanese Indigo break dormancy

Madder red and indigo bluedyed handspun and knitted jumper

From fleece to jumper in 6 years

By Ashley Walker
Copyright 11th February 2020

Ever since starting to grow our own dye plants I have wanted to create something I could wear, something that had been created from scratch. In the past I have been quite content to use bought materials to create works of art and craft but as I got older this has appealed less and less. I used to be confused by people who wanted to go back to creating the raw materials of their crafts. I thought that the raw materials were just tools to aid creativity and it was easy to buy the best. I never concerned myself about where they came from or how they had been produced. In time something changed and the thought of creating the raw materials myself began to be more important. I do not really understand the reasons why.

Growing our own dye plants was at first a sort of curiosity but one that propelled us into the world of spinning fleece. After all if you are prepared to grow your own dyes then it no longer seems right to use them to dye commercially manufactured textiles. What would be the point of that? So fleeces were obtained and Susan set out on the road of learning how to clean and mordant them. Later came carding, spinning (drop spindle and wheel) and plying into yarn with diversions into weaving and peg loom weaving. But learning all the steps to achieve a finished dyed garment has turned out to be a steep hill to climb.

Once I had learned how to spin I decided to dye sufficient fleece to make a jumper and trusted to my ability to learn how to knit when I had enough yarn.

Red madder dyed fleece being carded into rollags and spun into yarn

Red madder dyed fleece being carded into rollags, spun and wound into balls ready for knitting

The first photo I have of the beginning was taken in 2014 and shows some of the madder dyed fleece and yarn. However by the time this was taken I had probably been at it for quite a while. The dyeing process was done very carefully so as not to felt the wool. Chopped root was heated to about 60ºC and the fleece added. The dye pans were then placed in a hay box and left overnight. The next day the fleece would be removed and the chopped root at the bottom of the pan was pounded to help release more alizarin (the chief red dye of madder). The pot was then reheated and fleece reintroduced. This might be repeated 3 or more times before a suitable red was obtained.

Slowly, slowly I built up a good stock of dyed fleece to spin. The shades of red varied so I tried to blend the darkest with the lightest to obtain as even a result as possible. Even so the yarn shows a variation in colour which results in the very pleasing stripes of the finished jumper.
Once I had enough I needed a knitting pattern and I quickly found out that knitting patterns are created for consistently even commercial yarn, not home-spun. But with help from our good friend Brian Bond and a few test squares of my own knitting I ended up with a ‘sort of’ pattern I thought I could work to. This was adapted from a cardigan design in one of Brian’s books that I liked the look of. But that’s where it all came to a bit of a grinding halt. I started on the indigo dyed blue rib of one side of the jumper but after several weeks of trial, with much undoing I had barely got into the red. The level of concentration needed to knit was so great that the slightest distraction caused dropped or added stitches or some other mistake. Even when I thought I was concentrating I would often find myself knitting the wrong stitch and all this before I had got to the point of having to reduce the number of stitches or do any of the fancy edging. It was too much.

shows blue rib and a bit of the red dyed yarn knitted on circular needles

This is as far as I was able to take it on my own.

The wool and the bit of rib stayed in its bag for months until Susan took pity on me and decided to have a go herself. Susan can knit but has no experience of knitting with irregular yarn. So what did get knitted took a long time and wasn’t remotely the right shape or size. Susan was canny enough to know that sewing the pieces together would have resulted in an unusual jumper to say the least. So back into its bag it went. Then along came Tracey Ballard who said nonchalantly “Oh yes I’ll finish that off for you if you like”. It meant that my dream of doing it all myself was truly out the window but by this time I was a pushover to accept any help.

No doubt after much remedial work (we suspect more than has been admitted to) Tracey turned up with the finished jumper a few months later. It was exactly as I imagined it. It is heavy and warm and it fitted perfectly. It is the first new jumper I have worn since one my mum knitted me many years ago. I failed to do it all myself but the feeling when wearing it… well it’s indescribable. The colour red is bold and bright. Red was my fathers’ favourite colour. He would buy me red shirts for Christmas which I would never wear. Now I have a totally unique red jumper, one that could never be bought in a shop and one that I will be proud to wear and show off for the rest of my life. No doubt my Dad would have approved.

Ashley wearing the newly delivered jumper

The smile says it all.

Thanks to Susan and Brian for encouragement and advice. Special thanks to Tracey for finishing it off. It is friends and the small things that make life worth living even if they do take 6 years to complete.

shows rear of red madder dyed jumper with red stripes - the result of uneven dyeing

The back of the jumper showing the stripes produced by variations in the dye.

A monster in the greenhouse

Growing American Pokeweed in the UK
Phytolacca americana

By Ashley Walker
Copyright 20th January 2020

First a warning. All parts of this plant are poisonous to humans and most animals except birds. It is also invasive so its growing must be carefully controlled.

I had heard a lot about this controversial dye plant, but in the UK it’s still much of a novelty. So when I spotted some plants growing in a greenhouse nursery in Devon in 2018 I “obtained” a berry containing a few seeds. I grew them last year (2019) just to see for myself what all the fuss was about.

Horticulture

Three of my seeds sown in April germinated after about 2 weeks.

shows the baby seedlings growing in a seed tray

The three seedlings of American Pokeweed showing seed leaves and red stems

shows size of plant by late June already getting big and lush

By June the plant in the greenhouse was already looking like a lush spinach plant.

The pink stemmed seedlings were very vigorous and had to be potted on after a few weeks. By the time I judged it was warm enough to plant out in May/June the plants were already around 10in high. My first observation was how similar they look to our native Deadly Nightshade (Atropa belladonna) despite belonging to a totally different plant family. Pokeweed is sometimes called American Nightshade and I think this is not just because of its toxic qualities.

Not taking any chances with late frosts I planted one of the plants in our greenhouse and the other two outside in the garden. The plant in the greenhouse grew with extraordinary rapidity, its reddish stem swelling out to more than 2 inches in diameter. By the Autumn it had escaped through the window in the greenhouse roof reaching 7ft. An extraordinary “triffid” of a plant!  Outdoors the plants did not do so well only growing to about 4ft.

The pokeweed plant was so vigorous it had escaped through the greenhouse window

By October the plant had escaped though the greenhouse window and was threatening to take over the whole greenhouse.

Closeup shot of American Pokeweed flower spike

The pink flower stems are quite attractive.

The berries of American Pokeweed start as green then turn pink and finally black at which point they are ready to be used to dye.

Shows a different variety of Pokeweed with short clublike raceme of green berries.

This photo shows the other variety of Pokeweed with short “club like” racemes of berries. Spotted growing at Bell House.

A Large American Pokeweed plant growing in the Hornimams museum dye plant garden showing upright short racemes of ripe berries

A slightly out of focus shot of the mature American pokeweed plant growing in the Horniman’s museum dye plant garden showing short upright racemes of ripe berries.

There are several cultivars of pokeweed available commercially – the chief difference between them appears to be the shape of the flower and berry racemes. In one type the racemes are short, upright and club-like (sometimes given a separate species name P. rigida) and in the more decorative type they are long, thin and pendulous. The plant is a herbaceous perennial native to North America which can reach 10ft in a single season before dying back to the ground during the winter.

Our variety is the one with long thin pendulous racemes. Later in the year we found plants of the other variety growing at the Horniman museum dye garden in Forest Hill, South London and in the gardens at Bell House, Dulwich. At Bell house it grows as a weed which demonstrates how invasive it can be.

Dyeing Method

Once the berries had ripened and turned black I picked a few racemes and test dyed on a small piece of alum mordanted wool yarn. Internet advice indicates that the best method is to make a dye bath from several times the weight of fibre to be dyed in berries, heated with the strongest acetic acid you can get hold of. I had some 10% acetic acid left which I bought to fumigate an old bee hive. At this strength the vapour alone can rust steel so caution is required. Distilled white vinegar is probably the next best thing. The yarn quickly took a very pleasing bright red colour (much quicker and easier than madder) but the big question was how long would it last? Some dyers say it can last years and others say it fades within a matter of weeks. I hung up my sample in the window with half of it covered in foil to keep the light out.

Light fastness

After about 80 days I took it down and had a good look at it. The wool exposed to the daylight had indeed faded with the side facing the outside more faded than the side facing inwards. What is more the red is fading to a disappointing brown (in the photo it looks more orange than it actually is). The window is incidentally a north facing one so it would presumably fade even quicker in direct sunlight. The covered part of the sample still shows a good red. From experience of other fugitive plant dyes I would guess that textiles dyed with pokeberry could be made to last a few years if kept in the dark and only worn intermittently indoors. But I’m not sure it’s worth it. When freshly dyed the colour is fabulous and I’m sure that when the native Americans used it to dye their ponies they made a glorious (and terrifying) sight. But coupled with the potential hazards of growing the plant I think that its continued inclusion in our dye garden is in the balance. Susan is all for eradicating it immediately so it’s on borrowed time!

Light fast test yarn showing fading of red to brown

The upper part of this wool yarn sample was exposed to light in a North facing window for 80 days. The lower part which was wrapped in foil remains a good red while the exposed part has faded to brown (in this photo brown looks more orange than it really is.

The same yarn from an indoor photo showing the side of the yarn that was facing the window which shows more fading

This photo (taken indoors shows the side of the yarn that was facing the window which has suffered the most fade.

This side of the wool yarn was facing inwards and has suffered less fade. The bottom part was covered in tin foil and has suffered little or no fade.

Conclusions

The plants growing outside managed to resist light frosts but have since died back to the ground. By January the plant protected from the frost in the greenhouse still has green leaves. Information on the web says that the plant mainly reproduces by seed (which can remain fertile for 50 years) but it can also shoot from the roots. There is no doubt that my greenhouse plant has produced many long side roots and the plant is clearly making a bid to take over the whole thing. No doubt the phenomenal growth uses up a lot of soil nutrients too.

On balance I think that where pokeweed grows wild (in North America) and berries can be obtained in quantity via foraging, it can be a fast, fugitive and fun plant dye, but as a dye plant in the UK it’s probably not worth planting it, not when a good permanent red can be got from madder.

Additional information on Pokeweed can be found here:

https://www.fs.fed.us/wildflowers/plant-of-the-week/phytolacca_americana.shtml

http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220010427

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=27983

Horniman Museum Dye Garden:

Formal layout of the Hornimans plant dye garden

The Horniman museum Dye Plant Garden is well worth a visit.

 

https://www.horniman.ac.uk/get_involved/blog/planting-our-dye-gardens

Bell House Gardens:

https://www.bellhouse.co.uk/blog/2019/6/12/perfectly-picturesque-bell-house-garden-in-the-18-th-century

American Pokeweed berries beginning to ripen.

Shows Devil's Bit Scabious plant in early June with lush green leaves but not yet in flower. Inset is blue composite flower from previous year

Devil’s Bit Scabious as a source of indigo?

By Ashley Walker
Copyright 15th June 2019

Scan of page 62 of Traditional Scottish Dyes by Jean Fraser showing entry on Devil's Bit Scabious

Scan of page 62 of Traditional Scottish Dyes by Jean Fraser showing entry on Devil’s Bit Scabious.

Front cover illustration showing plant dyed yarns

Scan of original reference from Chemical Dictionary of Economic Plants aparently confirming that a blue dye can be obtained from this plant

Reference to Devil’s Bit Scabious from Chemical Dictionary of Economic Plants

Some years ago I came upon a reference to this bee-friendly and pretty blue flower being a potential source of blue dye in Jean Fraser’s book “Traditional Scottish Dyes and how to make them”. Jean attributed her information source to Ethel Mairet. In her 1916 “Book on Vegetable dyes” Ethel briefly mentioned that Devil’s Bit Scabious leaves, if treated like Woad, will give a blue colour but adds no further details. A quick internet search brought up a number of other references to this plant producing either a blue or green dye. Significantly an entry in “Chemical Dictionary of Economic Plants” (2001) edited by Jeffrey B. Harborne, and Herbert Baxter, states that fibres placed in an alkaline fermentation bath of the leaves will turn blue on exposure with the air, though the active chemical is not identified as indigo. Devil’s Bit Scabious (Succisa pratensis) a member of the honeysuckle family (Caprifoliaceae) and a related plant is Teasel (Dipsacus), which in turn is also mentioned as a source of blue dye – being apparently produced by dried flower heads.

At the time I was looking out for possible dye plants that had flowers that weren’t yellow, as this would make our dye garden a little more attractive to the eye. I am also a beekeeper and Devil’s Bit Scabious was being promoted as one of the most pollinator-friendly native flowers, so I set about obtaining some seed. I was disappointed however to find that although you can buy the seed it has very poor viability. My first attempt resulted in no germinations and the second attempt only produced 5 plants out of around 500 seeds. In the end I bought some plants from the Rosy Bee plant nursery and planted them in the dye garden where they have positively thrived. Finally (3 years later) I had enough plant material to try extracting the blue dye.

Method

Leaves of the Devil's Bit Scabious looking very much like Woad leaves

Basal leaves of Devil’s Bit Scabious which bear close resemblance in both size, colour and shape to Woad leaves.

All references to the extraction process say that the basal leaves should be used and that they should be treated just like Woad i.e. placed in an alkaline fermentation bath (possibly the urine bath). I was not happy about using urine, so instead opted for Jenny Dean’s recipe for hot extraction of indigo from Woad using ammonia as the alkali. In addition, I did a more conventional dye extraction by simmering the leaves for 1 hour and straining the liquor; then dyeing mordanted wool yarn in a heated dyebath with and without adding soda ash to raise the pH. Finally I set up a solar dyeing jar with leaves, wool yarn and some soda ash to make the liquid alkaline and set it aside in a warm place to ferment.

Results

Jenny Dean’s indigo from Woad extraction

After pouring boiling water over the leaves and leaving for an hour and straining, I obtained a pale yellow liquid.

Shows pale yellow colour of Devil's Bit Scabious liquid extract

Pale yellow liquid extract.

showing green liquid produced by adding ammonia

Adding the ammonia turned liquid a dark green.

 

 

 

 

 

 

shows colour change from dark green to orangy yellow after reducing agent added

Colour change after adding Thiourea Dioxide to the green liquid.

There was no sign of any free indigo nor the characteristic sherry colour from Woad. The next stage, adding the alkali and aerating was exciting because the liquid quickly went a lovely dark green, exactly as one might expect if there was indigo in there. I had my hopes up now for the first time! The next stage was to add a reducing agent and for speed I used a tiny amount of Thiox (Thiourea Dioxide). The colour of the liquid immediately changed to an orangey yellow – too fast for the normal indigo process.

Both samples of yarn shown are the same shade of white

Unmordanted raw wool yarn vs unmordanted dipped yarn. Left: raw wool; Right: dipped wool.

But I put in some un-mordanted wool yarn anyway and waited. I took the yarn out but obtained no discernible change in colour at all. Disappointment! I did several dips and left the yarn in for about 15 minutes, then did more dips, but sadly there was no colour change.

After drying, the wool does look slightly altered but it’s a bit of a stretch of the imagination to see any blue.

Later, I took some of the original green coloured liquid which had the alkali added and neutralized it with some distilled vinegar. The colour instantly changed back to yellow, indicating pretty conclusively that there was no indigo in it.

Color changes from green to orangy yellow when liquid is neutralised with white vinegar

lowering the pH of the green liquid with vinegar brings it back to an orange yellow.

Conventional extraction

Pale yellow alum mordanted wool top. Grey iron mordanted wool bottom

Mordanted wool yarn dyed in liquid extract before alkali was added.

Alum mordanted wool gave a pale straw yellow with no hint of green. Dyeing time ½hour.
Iron mordanted wool, unexpectedly, gave a rather nice slightly warm grey. Dyeing time 15mins.

Shows different colours obtained by mordanting the wool with alum, copper and iron

Colours obtained with three different mordants after leaving in alkaline Devil’s Bit Scabious dye bath over night.

After adding the soda ash, the liquid darkened off as expected to a greeny yellow though not as green as when using ammonia. Wool samples mordanted with alum, iron and copper were introduced and, after rinsing in clean water, produced a similar set of colours after about ½ an hour. At this point I decided to leave the samples in overnight. In the morning the alum mordanted sample was much the same but the iron mordanted sample had turned from grey to a warm brown. The copper mordanted wool was an attractive greenish bronze. Depth of colour had not increased during the night. Rinsing the yarn removed the green tint of the dye bath.

Discussion

The acute sensitivity to pH tells me that the chemicals producing the green colour in the alkali extract are not dyes and will not even attach to mordanted wool. The grey and light brown colours obtained with mordanted wool suggests that there are natural tannins in the leaves and also a yellow dye. The entry in the “Chemical Dictionary of Economic Plants” says the active dye chemical is a seco-iridoid glucoside. Internet searches suggest that these molecules protect the plant from predators and pathogens and are of interest for their anti-oxidant, anti-inflammatory and possible anti-cancer properties. I did find a reference to an iridoid called genipin which in a weak acid is reported to produce a soluble blue pigment in the presence of oxygen with potential as a food colourant. But to obtain this blue pigment seems to require a chemical laboratory! And there appears to be no logical chemical link to the indigo molecule.

I speculate that the mythical blue colour is one of those confusions that get passed from one source to another without anyone really testing it out. If by some miracle there is a blue dye to be had it is not indigo. Possibly someone at some point mistakenly put Woad leaves into a bath of Devil’s Bit Scabious, they are remarkably similar in shape and size. Or perhaps someone just assumed that since the blue/green was obtained in an alkaline bath identical to a Woad leaf extraction bath then they must be the same dyes.

Shows jar filled with leaves of Devil's Bit Scabious, water with a bit of soda ash added and wool yarn.

Hopefully this solar dye jar experiment is about as close as I can get to the original assertion that Devil’s Bit Scabious fermented in an alkaline liquid will give blue.

The results of the solar dye experiment will take some time. I think it is unlikely there will be any blue or green but we will see.

One further thought, there could be a bit of a pattern developing here, searching for a blue from Elecampane root (see blog post) I discovered a rather nice grey could be obtained. Here again I get another grey. Perhaps this is more evidence that the colour grey was often referred to as blue in earlier days.

Well, I’m keeping the Devil’s Bit Scabious in the Dye garden. It really is a fantastic pollinator-friendly plant and it looks good too.

For a further addition to this story please look at Leena Riihelä’s blog post on the subject where Leena has a recipe for getting green written by the famous botanist Carl Linnæus.

References

Handbook on Natural Pigments in Food and Beverages – Industrial Applications for Improving Food Color. Edited by: Reinhold Carle and Ralf M. Schweiggert. 2016.

Jenny Dean’s Wild Colour. http://www.jennydean.co.uk/

Riihivilla blog post  http://riihivilla.blogspot.com/2019/07/woad-japanese-indigo-and-devils-bit.html

Resources

Rosy Bee – Plants for bees.
http://www.rosybee.com/plants/devils-bit-scabious-succisa-pratensis

Image showing young seedlings of Japanese Indigo in premature flower

Premature Flowering in Japanese Indigo

By Ashley Walker
Copyright 10th June 2019

This year I’ve had two reports of people in the UK growing Japanese Indigo from our seeds and experiencing premature flowering in May. I also read with interest Deb McClintock’s blog post about her early self-seeded Japanese Indigo (in mid-Texas in the USA) which germinated in early February and flowered in May. In the first two cases the plants were not remotely big enough to harvest, so this is very disappointing – doubly so since once the plants put out flower heads the amount of indigo in the leaves starts to decrease. Deb McClintock was able to harvest her “bonus crop” but she noted that it had not grown as well as her normal summer crop. Ideally the plants should grow to a large size before flowering in August/September.

So what is going on and what can be done to prevent this?

In all plants, flowering is often stimulated by the experience of stress e.g. unnaturally high or low temperatures, insufficient water or nutrients and pest damage. However, in the above examples the plants were being treated very well. My first thought was that the main cause of the early flowering was day length. In all three cases the Japanese Indigo seeds germinated in January/February when the day length is short. However, I can’t rule out low temperatures since this is the middle of winter in the UK (latitude=50deg N) and the night-time temperature in Mid Texas is going to get pretty low. Also in the UK in 2019 we experienced a Spring with extreme temperature swings and unusually late frosts.

I can find no definitive information online to suggest that low temperature is a known trigger for flowering in Japanese Indigo. But looking in my copy of ‘Handbook of Natural Colorants’ I see that day length is reported as the critical factor for Japanese Indigo, but other influences are not excluded. However it does say that Chinese Woad (Isatis indigotica) will flower if it experiences night time temperatures below 10°C (50°F).

In all three reports of early flowering, the plants received no artificial lighting and were grown in relatively frost free conditions, although they probably did experience night time temperatures well below 10°C. But of course the day length conditions in mid-Texas are considerably less variable than in the UK. (Mid-Texas latitude is approx. 35 degrees North compared to approx. 50 Degrees North here in Southern England).

The Handbook of Natural Colorants recommends sowing Japanese Indigo in April in mid Europe, with a first harvest in July or early August just before the flower heads start to form. It’s interesting to note that by this point in our summer, the day length has started to shorten but night-time temperatures are usually still over 15°C (60°F), so that should rule out cold temperatures as a trigger and points the finger at shortening day length.

However, my own observations in Hitchin for 2018 is that flowering was very late (September/October) following an exceptionally hot long Summer and warm Autumn. This is a much later flowering than normal.  This is confusing because it suggests that the high temperatures prevent day length from being the dominant factor in triggering flowering. No doubt someone out there (perhaps the professional Japanese Indigo farmers) will know the definitive answer but at the present time I’m not sure if it is short day-length or temperature stress which is the most important trigger for flowering. But in either case the solution is the same.

In Southern England, no matter how warm the early Spring, don’t be tempted to sow your Japanese Indigo seeds before April, unless you are able to give them some artificial light to lengthen their day. Giving them a little warmth (particularly at night) is a good idea too. If the plants do start flowering early, pinching out the whole top of the plant may reset them back to vegetative growth. If the plants are large enough it may also work to take stem cuttings in water (cut out the flowering tips). If these measures fail, new seeds can still be sown as late as June in the South of England.

shows seeds being propagated with extra lighting supplied by a rack of flourescent bulbs. Purpose is to boost light levels to stop seedlings becomming "leggy" and also to increase day length

In my own case, I use heated seed trays and artificial lighting on a timer.

 

Happy growing!

References

Handbook of Natural Colorants (2009), edited by Thomas Bechtold and Rita Mussak, Chapter 7 by Philip John and Luciana Gabriella Angelini.

Deb McClintock’s blog, https://debmcclintock.me/2019/05/27/new-tools-dried-indigo/

Thanks to:

Brian Bond for the photo of Japanese Indigo in premature flower.

Sue Prior

Field Madder plant showing tiny pink four petaled flowers

Natures Rainbow Garden Update – Spring 2019

By Ashley Walker
Copyright 8th May 2019

The weather here has followed the pattern of recent springs by being dry, sunny and warm with cold intervals and frosty nights. Planting out of the Japanese indigo will have to wait for a week or two yet but most plants are thriving. Time to look at last year’s plantings and make an assessment of what has worked and what has not. Last year we embarked on growing a number of new plants, many of which are relatives of Common Madder. Of course many folks have said “What on earth are you doing that for? There is no better plant than Common Madder!” That of course is true but in the past many of these madder relatives were used as dye plants and prized for their colours so we thought we’d try and find out for ourselves how easy they are to grow and eventually what colours their roots will yield.

Wild Madder Rubia peregrina

We first started with Wild Madder (Rubia peregrina) three years ago now. Spring frosts have been particularly hard on the plants as their evergreen upper leaves are not particularly frost hardy.

Browned and crisped frost damaged evergreen leaves of Wild madder, Rubia peregrina.

Frost damaged evergreen leaves of Wild Madder.

Their native UK homelands are the southern coastline of Devon, Cornwall and Wales where they get warm sea breezes that usually prevent frosts, so here in Hertfordshire they are a bit out of their depth. However the roots are protected and soon shoot back once the warm weather returns. Getting a good harvest from the plant is going to take time, even without frosts it’s very slow growing so we’re not planning to dig any up until Autumn this year.

Shoot of Common Madder (Rubia tinctorum) showing browned shoot as a result of frost damage.

For the first time in many years our Common Madder shoots were badly frosted. Not a problem as the plants quickly produce new shoots

Even our Common Madder beds were badly affected by the frosts with many of the new shoots being crisped.

Field Madder Sherardia arvensis & Hedge Bedstraw Galium mollugo

Field Madder Sherardia arvensis A cushion of Field Madder growing under a Weld plant with Sawort to the left. This plant self seeded last year and has come through the winter without any frost or snow damage.

A cushion of Field Madder growing under a Weld plant with Sawort to the left. This plant self seeded last year and has come through the winter without any frost or snow damage.

Generally described as an annual weed, we discovered that given plenty of attention this plant is perfectly capable of going through the winter and withstanding any frosts. Does this make it a short lived perennial? Many hardy annuals can do this and provided they are watered and fed can keep on growing. As this plant has very thin roots, getting a harvest is obviously going to be a bit of a test so we’ve decided to do a little experiment by growing Field Madder and another similar relative Hedge Bedstraw Galium mollugo in large pots in a compost mix that should be easy to wash away from the roots at the end of the year.

Large plant pot containing seedlings of Field Madder Sherardia arvensis

Large pot with seedlings of Field Madder.

Hedge Bedstraw Galium mollugo

Large pot of Hedge Bedstraw seedlings.

Dyer’s Woodruff Asperula tinctoria

Over the winter I managed to get hold of some seeds from Rühlemann’s in Germany but unfortunately none of these have thus far germinated. As a native of the northern steppe lands of Europe and Asia this may mean they need vernalization. Some of the plants we obtained from Scottish plant nursery (Poyntzfield Herb Nursery)  died towards the end of last year. Plants placed in an ericaceous compost in tubs seemed to do better than those planted in the chalky soil of our Nature’s Rainbow dye garden. This goes against the generally accepted advice that the plant likes alkaline soils. However, It may be other factors were involved. All of our plants died back really quite early in the year and we were afraid they might die out altogether, but back they have come this Spring and they look quite healthy. They have reappeared at the edge of the planters, showing that last year they tried to expand by producing underground stems much like Common Madder. I guess that this means they are capable of also being quite invasive!

Feathery Green shoots of Dyers Woodruff Asperula tinctoria

New shoots of Dyer’s Woodruff in the alkaline soil of our dye garden.

Ladies Bedstraw Galium verum

This plant has done really well in a whole variety of settings and soil types. It’s also very well behaved with minimal spread. It looks good throughout the year, with pretty clumps of feathery foliage followed by a spray of small yellow flowers in the summer. With its historic interest as a bedding straw, its use in dyeing  and its versatility as an ornamental garden plant, I feel that this plant is a must for any dye garden.

Feathery green clumps of Ladies Bedstraw Galium verum growing next to the greenhouse.

Clumps of feathery green Ladies Bedstraw growing by the greenhouse.

Alder Buckthorn Rhamnus frangula & Purging Buckthorn Rhamnus cathartica

Alder Buckthorn Rhamnus frangula. New shoot showing "alder " shaped leaves and blossom buds.

New growth of Alder Buckthorn.

New growth of Purging Buckthorn Rhamnus cathartica

New growth of Purging Buckthorn.

We tried planting Alder Buckthorn, an acid soil loving shrub, in a variety of conditions. Those planted in ericaceous beds or tubs have done well but those planted out in a wild setting in the chalk soil here have suffered greatly, though it has to be said, the most damage was done by muntjac deer who clearly have a liking for it.
The Purging Buckthorn did less well, to my surprise. It’s not supposed to be fussy about soil type. No casualties, but the plants have not grown very much in the last year. Although it could be that this plant simply takes longer to get established. The new growth this year looks a lot better.

As yet the plants are too small to risk any harvesting but I suspect it is the Alder Buckthorn that will give the better dye.

Tibetan Madder Rubia Cordifolia (Indian Madder or Munjeet)

We are now the proud owners of one of these plants. Obtained from the German Herb nursery Rühlemann’s, this plant spent four and a half days in a box being transported across Europe, the English Channel and finally to our door and arrived in perfect condition! Many thanks to Rühlemann’s  for doing such a professional job of packaging it up, we have great admiration! The growing tips had faded a little during transit but greened up rapidly on exposure to light.
According to the literature these rather elegant looking plants should just be able to survive outside in the UK, though I’m not taking any chances until I’ve had a chance to propagate some cuttings.  At first sight it looks quite different to Common Madder but it has the same leaf whorls (but only 4 leaves to a whorl as opposed to Common Madder’s 4 to 6) and has hooks on the square and weak stems just like madder and cleavers. It obviously has the same growing strategy i.e. it clambers over other plants, holding on with its small hooks.

Tibetan Madder Rubia Cordifolia (Indian Madder or Munjeet)

The Munjeet plant about a week after arriving. Repotted to a larger pot and already starting to grow and looking very healthy indeed

Rubia Cordifolia plant just after delivery and repotting

Rubia Cordifolia plant just after delivery and repotting

We are ridiculously excited by this latest acquisition and look forward to see how it grows and what sort of dye giving roots it has. According to Cardon* its chief dye substance is munjistin which gives a very bright orange. Like common madder it also contains many other dye stuffs, including a very large range of yellow to red anthraquinones. Alizarin is present but only in small amounts so the overall light fastness is probably not as good. Cardon mentions that there are different varieties of cordifolia as well as a very closely related species (Rubia akane) that grows in Japan. Our plant is advertised as being from Tibet, so hopefully it will be able to cope with frost during the winter.

Self-seeding

Bed of hundreds of tiny self seeded Weld seedlings

A mass of tiny self-seeded Weld seedlings in the dye garden

Cota tinctoria

Self-seeded Dyers Chamomile seedlings

 

Madder Seedlings Rubia tinctorum

This year we have had a number of self-seeded Common Madder seedlings in planters positioned near the house. They have produced seedlings in the garden during the Autumn before now, but these usually die during the winter. I think the weather has been just right this year to encourage spring germination and the temperatures near the house have prevented any frost damage.

 

 

 

 

 

Finally a little note on self-seeding of dye plants. We have always tried to encourage plants to self-seed in our garden, with some success. We have been growing the plants for a long period now and the soil is loaded with seed. Weed plants have been under control for several years, so there should be nothing to stop those plants which can self-seed from doing so. So here’s a check list of what you need to do to follow suit:

  1. Allow your plants to flower and drop their seeds. This can produce, in some people’s eyes, an untidy garden but there are so many advantages including encouraging wildlife and saving your time growing the plants from seed and planting out every year.
  2. Keep your garden weed free.
  3. Dig your garden sparingly, preferably in the Autumn or Winter.
  4. Learn to recognise dye plant seedlings.
  5. Use mulch sparingly i.e. only on areas where you intend to plant out other plants. (Mulch supresses seed germination and encourages slugs and snails).
  6. Try and control slugs and snails. (I recommend organically approved slug bait [Iron phosphate] as a last resort).
  7. Water the bare soil if it becomes very dry.

Three varieties of Japanese Indigo Persicara tinctoria

Finally I have managed to sow all three varieties of Japanese indigo at the same time to complete our comparative studies (see blog post). Sure enough, it is possible to tell the difference between the long leaved variety and the broad leaf variety. Even the photos show the slight difference in foliage colour (the broad leaf being a more yellow green) and the long leaf plants are a centimetre or so taller. These plants are about 3 weeks old and grown under identical conditions. The intermediate variety more closely resembles the broad leaf.

Persicara tinctoria

3 varieties of Japanese Indigo at three weeks from sowing.

More Pests

We have found something that eats madder.

Rubia tinctorum pests

This is probably the caterpillar of the Orange Underwing moth, a known pest in the UK which eats a whole variety of plants. So we’re not surprised it’s had a go at our Common Madder. Fortunately there are not enough of them to do any real damage, but they do spoil the appearance of the plants. We can live with that, so no need to take any action.

Suppliers

Rühlemann’s herb nursery has an excellent collection of dye plants and seed for sale and don’t mind sending stuff to other European countries. Their service is excellent.

Poyntzfield Herb Nursery   Scottish herb nursery sells various dye plants and will sell Dyer’s Woodruff root cuttings. Recommended.

References

* Dominique Cardon, Natural Dyes : Sources, Tradition, Technology and Science   . The Definitive reference book of dye plants and dyeing. If you want to know what dye plants are native to the country you live in you will find the information here. A master work, expensive but worth every penny.

Our back garden

The Natures Rainbow Garden

Would you like to take part in a Nature’s Rainbow “Pilot” Workshop on Planning a Dye plant garden?

Planning and Planting a Dye Plant Garden

UPDATE 9 May 2019
Thank you everyone! We have been overwhelmed by the interest shown in this first pilot workshop.  If you would like to be added to a waiting list in case anyone drops out, or if you would like us to alert you about future courses, please get in touch.

We will post about how the workshop goes after 1st June.

_________________________________________________________________________

Saturday 1st June 2019, 1 – 5pm

Creating a planting plan for beginner dye gardeners, with tips from Susan and Ashley of Nature’s Rainbow. What plants to grow, when to plant, when to harvest, how to maintain the garden.

We have been growing and using dye plants in the historic town of Hitchin for over 14 years.
Help us to design future workshops to share our expertise.

5 places available. Contact us via this blog for further details and how to book.
£20 nominal fee required in advance to confirm your place.

This is a very reduced rate to recognise the fact that the views and feedback from the people attending will be helping to design a future workshop for Nature’s Rainbow.

Participants will have a tour of an established dye garden (as featured in The Journal of Weavers Spinners and Dyers https://www.journalwsd.org.uk/article/the-dye-plant-garden and hear how we manage the mix of annual, biennial and perennial plants within the constraints of our site. We’ll structure the session loosely, so we can maximise the flow of info between us all.

Seeds and perennial root cuttings of madder and small dyer’s broom plants to take away.

In exchange, you need to be willing to provide feedback and ideas on how to design future workshops and bring a simple sketch of your growing space, marking up sunny and shady areas and soil type.

Our house and dye garden is a very short walk from Hitchin Station, with frequent services on the Great Northern train line between Kings Cross, Cambridge and Peterborough.  Please contact us

Susan and Ash

Talk to Lea Valley Guild of Spinners Weavers and Dyers

12 April 2019
I had the pleasure of talking to this friendly guild last night about how to mordant safely for plant dyeing. The group meets in the beautiful village of Roydon in Essex, just across the border from my home county of Herts.  https://leavalleyguildswd.weebly.com/

Here are recommended links referred to in my talk.

Catharine Ellis blog – https://blog.ellistextiles.com/

Recommended books
The Art and Science of Natural Dyes; Principles, Experiments, and Results
By Joy Boutrup, Catharine Ellis (2019)
ISBN10-13: 076435633X : 9780764356339
176pp £57.99
UK distributors – Gazelle Book Services  01524 528500
You can order by phone – New stock arrives UK on 22 April.
https://www.gazellebookservices.co.uk/

The Modern Natural Dyer
By Kristine Vejar (2015)
ISBN: 9781617691751£18.99 from Waterstones
https://www.averbforkeepingwarm.com/products/the-modern-natural-dyer

Sustainable plant sources of aluminium and tannin mordants
Bebali Foundation  http://plantmordant.org/symplocos/

And finally … for safety gloves perfect for indigo dyeing

Gloves –  glovesnstuff.com

 

 

 

Whats New in Natural Dyeing

Exciting new publications for plant dyers

Beyond Mordants from Slow Fiber Studios

Susan and I have long been fans of Michel Garcia’s DVDs on natural plant dyes and pigments. So we were excited and delighted when we got an email before Christmas from Slow Fiber Studios asking to use some of our dye plant photographs for a new DVD:

Beyond Mordants: Indigo Intensive and direct application of Dyes. Film IV: Natural Dye Workshop Series with Michel Garcia

Publication date: February 2019.Michael Garcia and Slow Fibre Studios new DVD Beyond Mordants

Using metallic salts of Aluminium, Iron or Copper for mordanting is controversial in craft plant dyeing as these are all toxic to some extent, both to humans and other forms of life. If used and disposed of with care, the risks can be reduced [See Carrie Sundra’s blog] but many people choose to avoid using metal-based mordants completely.

As a result there has been growing demand to find safer alternative “bio mordants”. Promising plant substances include Myrobalan, various tannins, Curcumin (from turmeric) and Lawson (from henna). In this latest DVD Michel Garcia addresses this gap in current knowledge and shows how to dye and print without using metal mordants.

Slow Fiber’s DVDs are packed with information and can be watched over and over again. They are aesthetic, gentle, informative and a perfect antidote to a stressful world. A friend, Aviva Leigh from Norfolk was the first to introduce us to their work. She says the mark of a true plant dyeing friend is someone with whom you can, with eager anticipation, settle down for an evening of re-watching Michel and Yoshiko’s DVDs, just as others would watch the latest Hollywood blockbuster! The films are soul-food for the craft plant dyer.

It’ll be very exciting to see plants from our dye garden (our babies!!) on screen!

Michel Garcia. Still from DVD “Beyond Mordants” © Slow Fiber Studios

 

New Book: The Art and Science of Natural Dyes

If, like us, you are keen to understand the science of plant dyeing and mordanting in particular, a new book by Catherine Ellis and Joy Boutrup’s comes highly recommended.

The Art and Science of Natural Dyes: Principles, Experiments and Results by Joy Boutrup and Catharine Ellis.The Art and Science of Natural Dyes by Joy Boutrup and Catherine Ellis

This book has now been released for sale (January 2019).

Catharine Ellis is a weaver, dyer and author of international repute based in North Carolina. She specialises in systematic experiments in her craft and teaches through Slow Fiber Studios. Many readers will be familiar with Catharine’s excellent website (see here). Joy Boutrup, from Denmark, lectures in textile technology for fashion design and for museum conservation. Both women have longstanding and impressive careers in their respective fields.

It’s our feeling that both the DVD and this book will be landmark publications, marking a step-change in the systematic knowledge available to the craft plant dyer. So don’t be put off by the prices (Beyond Mordants $52, The Art and Science of Natural Dyes $60).

In our own small way, we hope that the observations that inform our blog are a useful information source, and it’s free! But essentially we provide small snippets of data. Collecting all of that information together into a structured form, providing an expert overview and binding it into a professionally referenced book or instructional DVD takes time and money.

It is my hope that one day I will have amassed enough information about growing dye plants to make it possible to write a book on the subject myself but it will take many more years of growing, observation and experimentation to get to that point.

I can only imagine how much work has gone into the two publications above. Even though I haven’t seen them at the time of writing, I feel confident to recommend them. They are the work of leading experts in the field and I for one can’t wait to get my hands on them!

By Ashley Walker and Susan Dye
© Nature’s Rainbow