Dyeing Wool with Hemp Agrimony

Madeleine Jude recommended I grow Hemp Agrimony (Eupatorium cannabinum). As you will read in this link, she used the flowering tops to dye yarn a strong yellow green. I was particularly interested when, in conversation on a Ravelry forum, she told me that unlike many dye plants, Hemp Agrimony likes damp conditions and copes with shade. Wonderful plant for a garden in Wales. I sowed a packet of seeds last Spring and the young plants did indeed thrive. I watered them regularly during the unusually hot weather in July and they grew about two feet tall and actually flowered this month.

Earlier this summer, I found plenty of hemp agrimony plants growing wild along my regular dog walking route. What is more, lurking round the back of the greenhouse in my own garden, I already had a mature plant, which grew about eight feet tall and fell over before I spotted it. Never let it be said I am too tidy a gardener. 

Once I was aware of all these established plants, I saw them flowering much earlier than my newly grown ones. In the heat of July, I was able to stuff a jar with flowering tops, which solar dyed some wool fibres vivid yellow, a colour much like Madeleine Jude's yarn. Which made me very pleased to have grown my own and a bit surprised that the plant isn't better known. There is little or no information about dyeing with hemp agrimony either online or in my books. Further exploration seemed well warranted.

Last week, I cut 300g tops from my young flowering plants and simmered them for an hour. The dye bath looked pale yellow (centre jar), adding vinegar made it go pale pink (left), while adding soda ash to make the dye alkali deepened the yellow (right).

Rummaging for some test fibres, I found three 50g skeins of Cheviot wool yarn which I mordanted with alum ages ago. Madeleine used a 1:1 ratio in her dye pot, this was a 2:1 plant to fibre ratio. The skeins were soaked and simmered for an hour and left in the dye overnight, but next day, their colour was dimmer than I had hoped.

I gave one skein a rinse then a soak in water with a little dissolved soda ash and its colour did brighten somewhat. Not as good as Madeleine's, but in retrospect, I now remember that this yarn does not pick up plant dyes particularly well. The two remaining skeins were heated again, one with copper and the other with iron solution (see below, right and left). 

Next year, I'll definitely be dyeing some nicer yarn. Now I appreciate how big they grow, I'd better move my young hemp agrimony plants to give them more space. Probably, as older plants, they will flower earlier and maybe that will also help in getting stronger dye colours in future.

Finally, one of those eeeek!!! moments. I asked himself to uproot the huge plant and clear the area behind the greenhouse. Major event next month, the old greenhouse will not have to be patched up again this winter, it is coming down before it falls down. Thanks very much, Mum, I have decided to squander my inheritance on a state of the art greenhouse of considerable size, beauty and style. 

Sod's Law, the same evening the big agrimony came out, I saw a fascinating snippet on Gardener's World. Last week's programme showed a group of women from Asia with a shared allotment in the UK where they grew hemp agrimony especially in order to dye fabric a purple blue with the seeds. Astonishing - I've sent an email to the BBC and if they ever do put me in touch with the group to ask about their method, I'll be having a go at that next year.