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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

Coreopsis tinctoria

Growing Dyer’s Coreopsis

An article by Ashley Walker
© copyright 2016

Dyer’s Coreopsis (Coreopsis tinctoria) Plains Coreopsis, Garden Tickseed, Golden Tickseed, or Calliopsis is an annual flower growing from one to two feet in height from the prairies of North America. It is very pretty with bright red and yellow flowers, now grown primarily as a decorative garden flower or as part of a “wild flower mix”. There have been several attempts to cultivate varieties better suited to the garden. I list some of the more successful cultivars below.

Mardi Gras” – Suttons seeds
Mahogany Midget” an all-red dwarf variety – Chiltern seeds
Roulette” a semi-double variety – Mr Fothergills and Kings Seeds
Quills and Thrills” a variety in which the petals form tubes – Thompson and Morgan
Incredible” a mixed variety – Dobies seeds (contains seeds of a white and red petal flower)
Radiata Tigrina” a jazzy variety – Chiltern Seeds
Coreopsis hybrida Incredible Dwarf” – Kings Seeds

All of these varieties have been created by careful and rigorous selection and the resulting cultivars will generally breed true. However they will easily hybridise with each other if grown close together. For the novice the best of these may be the dwarf varieties which do not require support.

Dyer#s Coreopsis

Variation in flowers

For several years we have been using saved seed, originally from a wild-type variety from Suffolk Herbs (now Kings Seeds).  This has produced a diversity of flowers, some almost identical to the varieties above. There is a huge natural variation in flower type which is passed on via cross pollination from year to year. The only named variety we have grown is “Roulette” which was not much different from the wild type.

Coreopsis tinctoria

An all red variety with pointed petals.

Coreopsis tinctoria

An average flower of Dyer’s Coreopsis. Some flowers have more yellow others less.

Dyer’s Coreopsis is part of a huge genus of plants in the Asteraceae family, many of which have also been used as dye plants. Tinctoria is distinctive in having a large proportion of red in the petals, so perhaps most of the dyestuff is in the red pigment? In this case, pure red flowers would be the best for dyeing. The majority of our flowers are deep red with a yellow outer edge. Some are completely red. A smaller number are intermediate. I would like to know if the red petal colour contributes a different pigment, but as all the flowers have a yellow underside to the petals, regardless of the surface colour, this isn’t an experiment I can do easily. Coreopsis, like Dahlia, contains dye pigments not found in the classic yellow plant dyes of the European Medieval Petit Teint. These are called chalcones and aurones. For a note on the chemistry and history see Dominique Cardon, Sources Traditions, Technology and Science (2007, pp683,4).

Dyer’s Coreopsis is invariably described as “Perfect for pollinators” by the Royal Horticultural Society, however, we have not seen any evidence of this over many years of growing.

Propagation

Coreopsis tinctoria

A young “rosette”  of Dyer’s Coreopsis with rounded leaflets

Coreopsis tinctoria

Another young seedling with narrow elongated leaflets. This plant has broken out of the rosette stage and is producing narrow mature leaflets and a flower stalk.

Coreopsis tinctoria

A densely planted bed of Dyer’s Coreopsis just coming into flower.

Dyer’s Coreopsis is prone to slug and snail attack so is best sown into seed modules (two or three seeds per module) in April and planted out in May with organically approved slug pellets. Root damage during transplantation will stimulate the plant to flower prematurely so care must be taken. It is generally considered to be hardy and in some areas of North America can be treated as a biennial and directly sown in Autumn for a spring flowering the following year. We have not tried this for fear of slugs.

There is great variation in habit, with some plants producing flowers early when the plants are small and others remaining as “rosettes” until late summer. Planting out early, after only a short time in the seed tray, will discourage early flowering. The plants will grow to a good size and give a much better display/dye-harvest. For spectacular displays plant seedlings close together (4 inches apart).

Here in Hertfordshire we rarely get any self-seeding (just the occasional plant) so we have to sow from saved seed every year.

Care and Maintenance

Faces to the sun
The flowers of Coreopsis all point south towards the sun, so in order to get the best display, grow them in a place where you can stand and admire them with the midday summer sun behind you. We usually plant these ‘en masse’ in a bed of their own. The photograph shows Coreopsis in a narrow bed alongside the southern edge of the greenhouse. In their natural habitat they get the support of other plants. In this location they would have benefited from some support to stop them flopping all over the path.

Dyer’s Coreopsis will grow in any soil type and does not require much fertiliser. Like Weld, it is best grown in rotation with Japanese Indigo or Woad. In the wild it likes to grow in damp places but prefers a well-draining soil. Coreopsis roots are shallow so the plant needs regular watering to grow larger and flower for longer.

Slugs have the habit of chewing through the main stem which usually kills or seriously delays the plant’s development. Apart from this they do not seem to suffer from other pests or diseases.

Seed Saving

Coreopsis tinctoria

Dyer’s Coreopsis seeds

Once the flowers have “gone over” the small rod-shaped black seeds start to mature. As a rough guide, the seed-heads will be ready for picking after a month. Bring them indoors to dry out completely. Rub the seeds out from the dried flower heads with your fingers into a shallow tray which can then be shaken from side to side and blown gently to remove the chaff. Stored in sealed bags and kept in a cool place, the seeds will remain viable for around three years.

Harvest

Dyer's Coreopsis in full flower

Dyer’s Coreopsis in full bloom in August with all flowers pointing towards the South

Dyer's coreopsis after picking

Dyer’s Coreopsis after picking flowers.

Before and after picking
Here you can see the same bed before and after picking. It took about half an hour to pick all the flowers in the above photos. A small footstool makes the job easier. It’s very calming to slow right down and enjoy the process. Only pick the flowers in full bloom, or those that have gone over. Leave the buds.  If you are in a rush, you can pick the whole plant, stalks and leaves included, but it is a terrible waste as the plants will come back into full bloom within a week.

Tools of the trade

PIcking dye flowers

PIcking dye flowers

We have a weakness for baskets. This is one of a set of five fairtrade baskets Susan bought from Oxfam years ago. They are perfect for flower picking. There’s no need for any cutting tools to pick the flowers. They pinch off very easily, but be careful not to pull them off vertically as the whole plant may come up with the flower.

Herb dryer with flowers

Close up of herb dryer

Herb drier

Herb drier is well suited to drying dye flowers

Dry flowers in storage jar

Dry flowers in the jar

We use a Stockli herb dryer which has served us well over many years. A fan in the base blows warm air up through a stack of trays. It’s well worth buying extra trays. We also use it to dry basil, oregano, rose petals and apple rings. Some flower heads, like Coreopsis, will dry in just a few hours but fatter flowers like Dahlia need a couple of days. To store well, herbs and flowers must be absolutely dry. Keep going until they feel dry to the touch. Then leave them for 24 hours in the trays in a dry place for any moisture remaining in the flowers’ centres to be drawn out. Then give them another short drying session (about an hour). This will reduce the risk of the flowers going mouldy in storage.

Make sure your container is truly airtight and store in a cool, dark, dry place. If you have done a good job the dried material can last for years.

dry dyer's coreopsis

Dried Dyer’s Coreopsis flowers

Dyeing with Coreopsis

The dyes in Dyer’s Coreopsis are highly soluble, so all that’s needed is to pour on boiling water and leave the flowers to soak. Susan added the dyestuffs to the baths in two batches. The yarn and one silk/cotton swatch went in with the hot water at the start. These were left for several days, removed and rinsed. The paler coloured cotton drill, cotton jersey and the other swatch of silk cotton were left in the exhaust bath for 48 hours. Again unheated. The results tend to confirm Jenny Dean‘s note in her book Wild Colour, that there are at least two pigments in the flowers, a red and a yellow. The red is probably taken up quicker than the yellow, hence the orange tone (yellow+red) is restricted to the early phases of the bath. The exhaust bath only contains the yellow.

Dyer's Coreopsis on silk cotton, main bath (left) and exhaust bath (right).

Dyer’s Coreopsis on silk cotton, main bath (left) and exhaust bath (right).

Exhaust bath Dyer's Coreopsis on alumed cotton jersey and cotton drill

Exhaust bath Dyer’s Coreopsis on alumed cotton jersey and cotton drill

Here are some samples dyed with flowers dried in a previous year. The yarn is cotton mordanted with alum. The various fabric swatches were cold mordanted by a long soak in 5% aluminium acetate. All samples were photographed just after rinsing so the colours will lighten on drying

DyersCoreopsis on cotton

Alumed cotton from strong Dyer’s Coreopsis bath

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Reseda luteola

Growing Weld

An article by Ashley Walker
© copyright 2016

Weld or Dyer’s Rocket (Reseda luteola) is a UK naturalised biennial wild flower that prefers to grow on chalk or limestone soil. It has pale yellow flowers and can grow to over two metres in height in its second year. The adult flowering plants are often seen growing in great masses on waste land or recently disturbed ground and may then mysteriously disappear only to pop up somewhere else another year. It has one common close relative, Wild Mignonette (Reseda lutea) which can also be used as a dye plant. Sweet Mignonette (Reseda odorata) is a closely related plant from the Mediterranean often grown in gardens for its attractive scent and as a bee attractant. All of these plants are well known for their perfume which is particularly noticeable when the plants are dried.

Weld is a Biennial

Reseda Luteola rossette stage

Two Weld rosettes in early spring

As a biennial, Weld is usually expected to grow from seed into a “rosette” in the first year. A rosette is a ground hugging form, where all the leaves grow from a central point. The plant  goes through the winter as a rosette, when there may be some die back during cold frosty weather. In the Spring the rosette grows new leaves and the central stem starts to emerge into a tall flower spike. Once flowering is over the plant is expected to die. Well that’s the official line, but anyone who has grown biennials will know that it all depends on how the plants are grown (see photo).

Reseda luteola

Above, large Weld rosette in October it has tried to put out a flower stalk but the shortening day length has stimulated it to return to its rosette stage. Below, Weld in full flower.

Reseda LuteolaLeft to its own devices, weld seeds get scattered from mid-Summer onward. Some of these seeds will fall to the ground and germinate during late Summer and Autumn and grow into rosettes as expected. Other seeds will lie dormant in the soil and await an opportunity to germinate, usually afforded by a disturbance to the soil (animals rooting about for grubs or roots or a gardener tilling the soil). These seeds will take their chances to germinate at any time of year when the weather is warm enough. Some seeds will germinate in early Spring and, if the conditions are right, may complete their entire life cycle in one year. If the plants are stressed for any reason e.g. by drought or physical damage, they are even more likely to flower. The later in the season the seed germinates the more likely it is that it will flower in the following year. Weld’s rather random flowering behaviour makes it an awkward plant to cultivate. It is also highly sensitive to any kind of root damage, so transplanting seedlings invariably results in numerous casualties and transplanting an adult plant is almost impossible. It is quite often the case that the best plants the garden grows are those that have self-seeded in a path or on the vegetable patch – in fact anywhere except the bed you have set aside for growing Weld! It is not for nothing that Weld is generally regarded as a pioneer plant – one of the first to colonise waste ground.

Propagation

Reseda luteola

Tiny round black seeds of Weld

The gardener interested in growing Weld for dyeing will seek to grow as large a plant as possible. This means allowing the rosette plants to build up good food reserves in their deep tap roots before shooting that ‘rocket’ of a flower spike up into the sky. This requires a certain amount of garden pampering and a choice of strategies.

Strategy 1

Reseda luteola

Reseda luteola

The same bed about two months apart. On the left the weld seedlings have been planted for a week or two and the leaves have turned brown. Two months later many of the plants have died.

Sow seed thinly into modules in early April under glass or indoors. Do not cover seeds with compost as light helps them to germinate. When the plants have grown to around the five to ten leaf stage, carefully plant out into prepared beds in mid-May. Do not add any fertiliser to the soil as research shows dye yield falls with increased nitrogen, but do water as needed. Continue to water the young plants, particularly in hot weather, and weed throughout the year. With luck, some of the plants will grow large and flower in mid or late summer when they can be harvested.

Reseda luteola

Close up of struggling Weld seedlings

Strategy 2

Sow seed thinly into modules in late August and plant out carefully when large enough and water regularly, particularly in hot dry conditions. Allow to grow and go through winter and they will flower in June/July the following year.

Strategy 3

Reseda luteola

Self-seeded Weld with a few Dyer’s Coreopsis plants I planted in the gaps to brighten the bed up a bit.

Obtain some seed heads from wild Weld and scatter the seeds in great quantities directly onto prepared beds in spring. Keep beds watered and weeded. Scattering a few organic approved slug pellets will help to protect the young seedlings which may or may not germinate.

Reseda luteola

Mature flowering plants in the background and first year rosettes growing in the foreground.

Now if this all sounds a bit hit and miss, it is!  When I grow the seeds under glass or indoors I certainly get excellent germination but lose many seedlings on planting out. Enough, however, survive to produce adult plants some of which I allow to set seed. If this is done over several years the seeds accumulate in the soil and self-seeding will start. Note: to stand any chance of self-seeding the soil must be kept bare i.e. free of weeds and any kind of mulch (mulch suppresses seed germination and harbours slugs and snails). Remember, Weld is a pioneer plant and does not like competing with vigorous perennial weeds. Small rosette plants can be moved from inconvenient positions if carefully dug out with a large clod of earth around the roots.

Mass Planting

Weld does not make a particularly attractive garden plant in its rosette stage but if grown in ‘mono-culture’ it can put on a surprisingly good show when it flowers. If there are gaps in the first year Weld bed you can interplant other dye plants for added colour. Coreopsis is particularly good in this respect as it is an annual.

Reseda luteola

Mass planting of Weld

Harvest

Reseda luteola

Weld harvest

Right, dried Weld and Left, freshly harvested Weld being cut up ready for dye extraction.

 

 

 

 

 

 

 

 

 

Harvesting the plants just after they begin to flower in June is generally considered the best time. As the leaves begin to die off the amount of yellow dye starts to diminish, however, dyestuff can be obtained from the rosette leaves and from old plants that have finished flowering. All parts of the plant except the roots yield dye, including the stalks. Weld plants can be very big and take up a lot of storage space. If the plants are hung up to dry somewhere warm, dry and dark they will remain green, but if dried in the light they will turn a straw yellow or even bleached white. They will however still give good dye colour. Once dried the plant can be chopped up to save on storage space and kept in boxes, bags, storage jars etc. in a dry place.

Harvesting from the wild

Weld is often found growing on waste or disturbed ground, road verges and rail cuttings, so it is not that likely that anyone would complain about people picking it. However, the law is clear “it is illegal to uproot any wild plant without permission from the landowner or occupier. Uproot is defined as to dig up or otherwise remove the plant from the land on which it is growing, whether or not it actually has roots”. Occasionally we do harvest from the wild but we always try to be responsible by cutting the plant stalks (not pulling up the roots) and leaving plenty of plants to seed.Reseda Luteola

Persicaria tinctoria

Growing Japanese Indigo

An article by Ashley Walker
© copyright 2016

Japanese Indigo, Persicaria tinctoria or Polygonum tinctoria is a frost tender member of the knotweed family. Originally from China and Vietnam it likes to grow in warm moist climates, often as a waterside plant. Our closest relative in the UK is Common Bistort or Persicaria bistorta which closely resembles Japanese Indigo but has no trace of indigo in its leaves (I did try once) though it does give a pleasant orange on alum mordanted material. Japanese Indigo will grow from seed to flower in one season and, if it does not get frosted, is capable of growing into the second year though here in the UK getting a plant through the winter is very difficult even indoors with extra lighting. We grow Japanese Indigo because it gives more indigo than Woad (approx. double the amount) and the colour is generally cleaner and more predictable than Woad.

Varieties of Japanese Indigo

There appear to be two distinct varieties though I have not seen anyone put a name to them.

Persicaria tinctoria

Pointed Leaf Japanese indigo

Pointed leaf Japanese Indigo. This is grown as an indigo dye crop in Germany and may have been selected for its ability to grow in a northern climate. It has pale green stems and white or pale pink flowers. The leaves are narrow and pointed.

Persicaria timctoria

Round Leafed Japanese indigo

Round leaf Japanese Indigo. This is the variety most commonly grown in gardens, perhaps because it produces a profusion of pretty deep pink or white flowers. Its stems are thick and also have a tendency to be pink. It seems less adapted to a northern climate and in poor weather struggles to grow – when first planted out, the leaves often go pink or yellow at the tops of the stems and continue like this if growth is slow. When grown in a greenhouse or polytunnel however the plants are greener, although I have not noticed any difference in indigo production between the two.

Growing Japanese Indigo

Persicharia tinctoria seedlings

Some of my seeds are “tricotyledons” and these germinate with 3 baby leaves rather than the usual 2. This is an uncommon mutation and may be a sign of inbreeding.

The shiny black seeds have only a short life (about a year if stored in a cool dry place). They can be frozen in the freezer and will last longer. To freeze the seeds first dry on a windowsill then place in a sealed plastic bag with a packet of silicon desiccator for a few weeks then pop in the freezer. Note: seeds frozen in this way tend to germinate slowly and may take up to 5 or 6 weeks to germinate. Commercially bought seeds are often stored frozen so don’t be too alarmed if you get no germination’s in the first 2 weeks. Interestingly I tried drying some seeds with a hair dryer on a low heat setting from a distance and found that this treatment also put the seeds into a deep sleep.

So, using some fresh seed grow in heated seed trays indoors from early April or late March. Sow thinly and cover with a thin layer of compost. Once germinated try to give them as much light as possible as they will grow “leggy” if kept on an average windowsill. The seeds should germinate readily within two weeks but occasional seeds may not germinate for a month.

Persicharia tinctoria seedlings

Seedlings with secondary leaves at around 4 weeks

The plants are very robust and rarely succumb to disease or pest, they will also transplant readily and can be pricked out at an early stage and potted up if you wish to do this. I usually leave them to grow in the tray until I am reasonably sure there will be no more frosts. Here in Hertfordshire that’s usually around the 6th May. By this time the plants will be quite large and the trays root-bound, some of the plants will have put out secondary roots from the stems and rooted in more than one place. Separating the plants out is therefore difficult and it is best to soak the tray in a bucket of water before trying. Do not worry about breaking the roots as Japanese indigo will re-root itself with ease. Planting in May is only advantageous if the forecast is for warm and sunny weather. If the forecast is for cold overcast weather wait until June before planting out.

Dye plants waiting to be planted out

Trays of dye plants waiting to be planted out including some root bound Japanese indigo.

Persicharia tinctoria

These plants stayed much the same size for 2 months before finally starting to grow in August of 2016

Persicaria tinctoria

These Japanese indigo plants were mostly planted on the same patch of ground as last year and only the plants to the rear of this bed were planted on fresh soil. All the plants were equally manured.

Weather is critical for good plant growth as you must remember this is a semi tropical plant. Sometimes the weather never really becomes ideal, in the cool dark summer of 2012 the plants grew hardly any larger than when I put them out. The plants were pale and looked sickly and there was no harvest. This year (2016) many of the plants also grew very slowly because the weather in the early part of the season was cool, wet and cloudy. It was not until late July when the weather improved that they really started to grow. If you have plenty of seedlings you can plant them about 4 inches apart in a heavily manured soil. Both Woad and Japanese indigo require lots of feeding to get a decent sized plant. Manure is the best if you can get it, but other fertilizers will do. Soil type is not much of an issue and the plants will grow on any soil. Clay loams are probably the best. My plants are grown on a poor chalk soil and I have problems with some nutrients in the soil being used up very quickly. Crop rotation is important for me as the plants do not seem to grow well if planted in the same area as the previous year. All my indigo beds need to be given a second feed in August particularly if I cut a first crop and allow the plants to regrow. Even so, many plants regrow with yellow leaves indicating they are short of some vital nutrient.

Persicaria tinctoria roots

Roots grow readily from the stem nodes.

If you only have a few plants and want to grow more from cuttings you are in luck as Japanese indigo is one of the easiest plants to grow this way. Just cut off the stems from about 6 inches above the ground and place in a container of water. New roots will grow immediately from the stem nodes and the cuttings will be ready to plant out in two weeks. Alternatively just stick the cuttings directly into the ground and water well (each day in hot weather) until the new plants are established.

Maintenance and harvest

As a waterside plant Japanese indigo is used to having its roots in water and it follows that it will grow very poorly in dry well drained soils. In the summer months of June to August I have to water my plants nearly every day because I have a light chalky soil. Once the plants achieve total ground cover they act as a shade and help keep the soil damp but they still need water on a regular basis.

Persicaria tinctoria

Take the first cut about 8 inches above ground leaving plenty of leaves on the plant.

This year I grew some Japanese indigo amongst other plants. I was surprised how well it responded to the competition, growing taller and greener. In a good year it is possible to take two or even three harvests of the plant. The stems are cut about 6 to 8 inches above the ground and the plants soon grow back. For an added boost to your harvest once you have stripped the leaves off the stems the now leafless stems can be placed in buckets of water with a dollop of liquid fertilizer and they will also grow quickly back. The stems alone have no indigo content.

Persicaria tinctoria stems

Stems of Japanese indigo after leaves have all been stripped off.

Persicaria tinctoria

The stripped stalks when placed in buckets of water with added liquid fertilizer will rapidly regrow and provide you with an extra harvest.

Indoors or outdoors and growing for seed

Persicaria tinctoria

Growing in a greenhouse it was possible to plant the seedlings out earlier but even then a mild frost in early May damaged and killed some of the plants.

 

Persicaria tinctoria

Frost damaged seedling in the greenhouse in May 2016.

Persicaria tinctoria

 

 

 

 

 

 

 

 

 

 

Persicaria tinctoria

Persicaria tinctoria

Japanese indigo does not need to be grown in a greenhouse or polytunnel unless you live far to the north but it clearly prefers being indoors growing lushly with greener, larger leaves and does not produce flowers until later so has a longer season.

 

 

 

 

 

 

 

 

Japanese indigo needs a long growing season to flower and usually only comes into full flower in October. It is self-fertile so will produce seed in a sealed greenhouse but will flower sooner outside in full sun. However, If frosts or bad weather are forecast before the seed has set be ready to dig a few up and transfer to greenhouse or poly-tunnel or bring indoors in pots. In the North it may be best to grow Japanese Indigo in a greenhouse or poly-tunnel. However, because it flowers later it may not be possible to get seed unless the greenhouse is heated. Some growers have reported that it is possible to get plants through the winter by bringing them into a well-lit and warm area where they will flower early the following year and produce seed.

Persicaria tinctoria

This miserable looking plant flowered in June and as you can see has been highly stressed with stunted growth and pale leaves with a pinkish blush

Persicaria tinctoria flower with honey bee

There are always a few plants that come into flower before the rest and it is best to leave these alone when you harvest. A few years ago I began an experiment to try and breed a variety of early flowering plants so I could be sure of getting some seed even in a bad year. This went according to plan and I ended up with plants that flowered in early September and some in August. However, once the plants start to flower the amount of indigo in the leaves starts to reduce and in full flower the yield is very poor. This led to lower harvests overall. Another strategy you can use for getting seed is to grow a few plants in a dry bed only giving them enough water to keep them alive. These plants will become stressed and will flower earlier – they may look miserable but the seed will produce nice healthy plants next year. Interestingly when the plants are in full flower they are very attractive to bees particularly honey bees. I wonder if honey can be obtained from the German fields of Japanese Indigo, as is possible with the fields of Woad in Norfolk.

Persicaria tinctoriaPersicaria tinctoria seed

Persicaria tinctoria

Seeds from the flowers in the greenhouse. As bees and most pollinating insects could not get into the greenhouse it looks like the the flowers are self fertile.

When the flowers go brown they can be cut and hung up or laid out to dry and some of the seed will fall out. The remainder can then be rubbed out. Separating the seeds from the “chaff” is a skill all by itself. Once you have removed the seeds and dried flower material from the stalks, place the whole lot in a tray and shake from side to side. All the heavy seeds will settle to the bottom and if you are careful you can blow the chaff from the top. This can be a dusty business so you must be careful not to breath it in. Some of the seed will retain an outer layer of brown chaff bound to the seed; this does not impair germination.

Persicaria tinctoria direct dye

Take a few handfuls of leaf and crush them up in a suitable container or blender. Add some white fibre immediately to the mix and leave for an hour. The colour obtained is rather dull and is not wash fast but will give you a good indication of how good your indigo is.

When new to dyeing with Japanese Indigo and Woad it is common to wonder how indigo was discovered as the plants apparently do not produce anything obviously blue though occasionally leaves will die and turn a dark grey or blue black. I suspect that someone observed that when crushed the fresh leaves will release indigo but it is only noticeably blue if you then add some white fiber to them. This is a good test to see if your indigo is ready to be harvested.

Persicaria tinctoria

The broken leaf has turned bluish black

Persicaria tinctoria

After the first frosts of the Autumn the upper exposed leaves have been killed and turn a dark bluish black. The indigo has become fixed into the leaf and can only be extracted using a special technique where a reducing agent is applied to prepared leaves.