This native plant is best gathered in the early to mid spring and can be found growing abundantly on riverbanks, in hedgerows or around freshly disturbed ground. To get the most out of the plant, pick only the tender tops - the first four to six leaves - this is the freshest growth and holds the most potent colour. As always if you are foraging in the wild, be sure to leave the majority of what you find behind.
I have had some of my most successful experiences using dried leaves so if you find yourself with an excess, don’t waste them! Simply tie them in bunches and hang upside down until they are crisp. Alternatively you can spread them flat on kitchen towel or newspaper and leave in a dark spot for about a week, these are then ready to store in a jar or paper bag until you need them.
To prepare the dye, cut the leaves into small pieces - after checking them over for bugs & insects - and cover with boiling water before leaving to soak overnight. I used 100% WOF of fresh leaves. Check your brew in the morning, if it still seems light in colour, bring it back to a gentle simmer in your stainless steel/aluminium dye pan [an iron pan works too but will affect the colour] before removing from the heat again to steep as it cools. You will probably need to repeat this process several times over the next couple of days, coaxing the colour from the leaves until you have a dark green, almost black, liquor. [Keep a close eye on it as once the leaves start to go off and ferment the smell can be very unpleasant - comparable to an unfortunate combination of sewage and bad seafood].
Test the colour with a swatch of fabric and once you are happy strain out the plant material through a muslin cloth before adding your pre-wetted fibre, ensuring there is enough liquid to cover it. Place on a gentle heat to almost simmer for about an hour, stirring frequently, then remove the pan from the heat and leave it to cool overnight.
The piece of antique silk was pre-mordanted with alum, and the cotton with soy, resulting in a wonderfully earthy greyish green. The colour would be stronger had I used a higher ratio of plant matter to fibre (perhaps 2:1) - also if I had picked the leaves earlier in the season - but I am still very happy with the results. I added a dash of rust solution to the dyebath for my final test on silk noil (top), as an example of how iron can sadden the colour, producing a more muted grey shade.