A Trial of Dyeing with Ragwort Flowers

I fondly imagined that once I stopped work, all that free time would mean the garden was kept much tidier and more productive. The reverse has been the case.  I wake up with a great list of things I fancy doing and weeding rarely seems a priority.  Horticulture has slipped to such a point that this week, my companion noticed there was ragwort flowering by the front path, where I used to grow weld.  She backed away in horror.
"I'm not being funny, Beaut, but that ragwort is toxic stuff."  

Having persuaded the man himself that the whole front garden could become a trendy wild meadow, if we just let the grass grow tall all over it, I was pleased to see a few new plants moving in. Elinor Gotland stood well clear as I opened the front gate for her.  
"Mind out, you can get a nasty rash from ragwort sap. If I were you, I'd stop messing about and get rid of the whole lot." 
"If I were you, I'd have eaten it all.  I thought sheep were supposed to keep fields clear of ragwort.  You didn't fancy nibbling off the young shoots this spring, then?"
"Ooo, no."  She glanced at my midriff.  "Some of us take care of our figures.  And it's terribly bad for the liver." 
I suppose her liver does have a lot of sloe gin to cope with. For the entire walk into town, Elinor lectured me on herbicides and how simply pulling the ragwort up would just mean bigger, bushier plants next year.  I rather liked the flowers and had no intention of unleashing chemical warfare.

Searching Wikipedia, I found there are four kinds of ragwort in the UK.  Mine look like the common type, Senecio jacobaea.  While it is poisonous to livestock, I can't see it doing much harm in a garden and it does add a cheery brightness.  The entry notes that the leaves will dye green and the flowers, yellow, which of course, made me wonder about dyeing with mine.  Websites often claim that plants will dye all sorts
of colours, past disappointments have made me wary.  I found this excellent blog, which seemed more plausible, considering my own track record of beige results and also, this one, written by someone I know and respect online, which made me feel considerably more optimistic about having a go.
Putting on gardening gloves, I collected over 1 kg of flower tops from the garden.  Took the dog for 

a walk and had as much again stuffed into a carrier bag by the time we got home.  
"You're mad as a box of frogs, bringing that horrible stuff into the house.  We shall all be poisoned by the fumes."  My companion flung out of theback door with her nose on the air, while I rammed the dye pot with the whole 2.5kg, brought it up to a low boil for a couple of hours and left it to cool. 

Once the flowers had been sieved out, the fluid had a strong golden bronze colour which changed very little with vinegar added - jar on left, and deepened to brown with soda ash as an alkali - jar with spoon.

Deciding to go for maximum effect at a ratio of 100:1 plant weight to wool, I simmered 25g white fleece, scoured and mordanted with alum. It came out a bit greener than the photo, not quite beige, but not a vivid yellow either. On the right, the colour did deepen after a soak in alkaline soda ash.

When I came out to check the colour of the dried fleece , I found my companion had already made a unilateral strike on one area of my meadow garden.  I wasn't sorry. That reopened border by the path got planted up straightaway with some trusty classic dye plants - weld and woad and madder.