Woad you believe it?

It does stink, but without woad, Braveheart would have been very pale-faced. Julia Platt Leonard investigates the natural dye once responsible for bobbies’ blue uniforms

Pungent, but pretty, woad was a vital dye, says Julia Platt Leonard

Historically, leaves were fermented and composted, giving rise to the terrible smell

WHAT does fermenting woad smell like? It’s hard to find the right words, but, luckily, plantsman and natural dyer Ashley Walker can see I’m flummoxed. Mr Walker and Susan Dye (yes, really) grow traditional plants—such as weld, madder and woad—for dying fabric and yarn. He looks from the jar of woad to me. ‘Halitosis,’ he declares with a smile. ‘Really bad halitosis.’

Mr Walker is right. The jar of woad slurry smells like the worst breath imaginable. I stare at the jar and wonder why anyone would willingly go near it, let alone use it to dye fabric. The answer is that woad, the plant Isatis tinctoria, contains indigo, one of the most coveted colours throughout human history. ‘There are many different plants around the world that contain indigo and woad is one of those,’ notes Flora Arbuthnott, natural dyer, grower and forager.

To understand how important woad was, gaze at a medieval English tapestry or the Lindisfarne Gospels. The colour blue? It came from woad. It was even used to dye police uniforms their distinctive shade.

Carolyn Griffiths charted the history of the plant in her book Woad to This after she happened upon an 18th-century dye-recipe book, read about woad and was hooked. ‘The whole of the South-west of England, and Frome in particular, was home to the cloth trade,’ Mrs Griffiths says. This made woad highly prized and she has traced cartloads that journeyed from Europe to Southampton—and on to Frome, Somerset—as far back as 1369. The people of Frome ‘were described as “blue with the manufacture of cloth”’. In England, woad was farmed by bands of travelling workers. ‘They went from farm to farm, so they would erect temporary buildings and process the woad, which is very time-consuming,’ elaborates the author. ‘Woad depletes the soil of nitrogen, so they would lease land for a couple of years, sow the crop, process it and then move on.’

This itinerant life isolated woad growers from other farm workers, as did the smell. So odoriferous were the vats of fermenting woad that Elizabeth I forbade woad-dying near her palaces or market towns.

The arrival from Asia of Indigofera tinctoria, or true indigo, reduced our reliance on woad. ‘You need a lot more woad to get the same amount of colour as you would from Indigofera tinctoria because it’s weaker and doesn’t contain as much pigment, but the pigment is the same,’ says Miss Arbuthnott.

It was the discovery of synthetic dyes that posed the biggest threat to woad and other natural dye plants. It started with a scientist named William Henry Perkin (1838–1907). ‘He was looking for a cure for malaria and accidentally discovered the colour purple instead,’ reveals Babs Behan, natural dyer and author of Botanical Inks.

In the late 1800s, a German chemist named Adolph von Baeyer discovered how to synthesise indigo. Synthetic dyes were cheap and produced consistent results, threatening to make highly skilled dyers, natural dying and woad a thing of the past.

Although commercial woad cultivation died out, the love of the plant didn’t. ‘I think it’s a part of who we are to use plant-based dyes. It’s a completely different culture, a completely different approach,’ ponders Miss Arbuthnott. ‘It’s about creating handmade textiles that are looked after, rather than our throwaway culture.’

Natural dying is also more environmentally friendly, which is one of the things that drew Miss Arbuthnott to natural dyes. ‘I was using a lot of synthetic dyes and really noticing the toxicity of them—it felt as if I was poisoning myself,’ she laments.

But what of the smell? ‘Dyeing with woad is, at its simplest, a two-stage process— extraction of indigo, then dying,’ Mr Walker points out. ‘Historically, leaves were fermented and composted, giving rise to the terrible smell that caused woad workers to be shunned by the public.’ He and Miss Dye steep woad in water for a few days, rather than using the more intensive fermentation method, and the resulting aroma is far milder.

Miss Arbuthnott offers a simple technique in her workshops: ‘You pick the leaves, add a spoonful of salt and then massage them. It’s a bit like making sauerkraut. The leaves start to release a green juice and you can use that to dye fabric blue immediately.’ She adds that, although synthetic indigo dyes may be the norm, it’s actually fairly recently that we abandoned plants such as woad.

How incredible to think that, without any understanding of chemistry, our forebears discovered how to unlock blue dye from an unassuming green plant with yellow flowers. Because, on the surface, there’s not a hint of blue about woad. The Blue Peter moment happens when you dip a skein of yarn or piece of cotton fabric into a vat and then lift it out.

‘It is magical—it comes out of the vat a pale yellow, turns green, then blue, in front of your eyes,’ says Mrs Griffiths. Reason enough, I’d say, to rediscover the wonder of woad.