Alchemy with fennel

I must admit that I don’t cook with fennel all that often, although I do love it as a herbal tea. My parents planted some in their vegetable garden this year, and have grown so much it is practically a hedge. And so, predictably, I stewed some up for dyeing purposes.

Many, many garden plants and herbs will give shades of yellow, but fennel will also give various shades of green if iron or copper is used as a mordant. First of all I mordanted some Bluefaced Leicester wool fibre with alum (10% WOF) and then I made up a dye bath with all of the fennel plant except the root. There was three times the weight of fennel to the weight of fibre. I simply dyed the fibre by simmering it very gently in the dye bath, and then allowing it to rest in the still warm liquid. Total time, about an hour and a half. Result – vibrant, almost neon yellow.

DSC_0237Next I took some merino fibres that I had dyed in a solution including logwood and a rusty horseshoe some time previously. The overall colour of this fibre to begin with then was white with grey streaks. Without reheating my fennel dye bath, I added more rusty objects, and put this iron pre-treated fibre into the warm liquid. I left it for around an hour. The result was a lovely moody grey/green. You can see it drying, above.

I was encouraged by this result and so the following morning, I inspected my dye bath, which had been left steeping with quite a lot of chopped fennel, rusty iron objects and warm water overnight. Chemistry had been taking place – I’ve read several natural dye manuals that suggest time is sometimes your best ally to get beautiful colours. So I put in more of the same iron pre-mordanted merino, and reheated the dye bath gently for around ¬†half an hour. Without having added any more plant material to the dye bath than I had to achieve the first, bright yellow colour, I got a beautiful strong, forest green.

Finally, I dropped a piece of unmordanted merino blended with around 10% silk into the still warm dye bath for around half an hour, just to see what happened. The result was much paler – a very soft steely grey with just a hint of green to it.


The colours are in the order I’ve described dyeing them, right to left.

I’ve already begun spinning some of the bright yellow along with the carrot-top dyed fibre. I’ve harvested woad from my own garden, carrots from my brother’s and fennel from my parents’. Whatever I make from the resulting yarn will have a whole family of gardens woven into it.

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  1. Love it! grey wool is so beautiful. what a great dye project!

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