The rhubarb in my garden tried to flower recently, which would have meant no rhubarb pies this year, so I cut off the flower bud and its large attached leaf.
You can’t eat rhubarb leaves as they are poisonous due to their high content of oxalic acid. I’d just recently read, in India Flint’s Eco Colour: Botanical Dyes for Beautiful Textiles that rhubarb leaves are a good source of dye and also mordant.
A mordant is a dye fixative and there are acid and alkaline mordants. The acidity/alkalinity of a mordant affects the colours produced when printing with plant material. A red flower might turn up black in a print, for instance.
So I chopped up the rhubarb leaf and for a couple of hours, in my copper dyeing pot, I boiled some sample pieces of muslin, cotton, various papers and for the first time, silk. I loved the result, especially the silk. I can see why silk is the preferred textile for dyeing.
The colour is a mix between beige and green, I think. The depth of colour differs between materials. In this case, the deepest shade is the silk; the palest, the khadi paper.
In another post I’ll show you what happened when I bundled the dyed/mordanted materials with some plant matter from my garden and freezer stash. I also bundled a selection of raw i.e. unmordanted materials, to compare the results. I steamed the bundles for two hours over the rhubarb leaf dye.
I didn’t get what I expected. Not at all. But I like that I can do something else with rhubarb leaves other than compost them. Dyeing fabric slowly by composting is another method of dyeing I’m looking into. Guess what’s going into my allotment compost heaps later this year?