Yellow Flowers ofSt. John's Wort(hypericum perforatum) are found along grass verges. I discovered them along the Tarka Cycle Trail on embankment which borders the River Torridge North of Bideford.
The Tarka Trail old rail track - Barnstaple to Bideford was my 10 mile route for foraging - using Jenny Dean's plant spotter book. Late summer finds many of the traditional dye plants along grass verges, especially in areas untouched for ages.
Dye Bath Procedure
Soak flower tops overnight in rain water. I use pond water.
Boil up and simmer for an hour
Coolliquid until hand hot, not to roughen silk, soak silk, stirring occasionally.
Leave overnight to absorb dye colour
Dye a second piece of silk using up remainder of dye
Second dye bath
First dye bath absorbs a lot of colour.
Second silk piece added on top through the night.
2nd day: Remove first stronger dyed silk piece and rinse out, not squeezed too much and leave to dry.
Drain seeds and flowers and heat remaining paler dye bath. Add second piece again for half a day.
Rinse out when water completely clear. Colour was blotchy, so I cut it in half.
Olive Green/Khaki Results
I heated dye bath again, allowed to cool, before adding tablespoon of ferrous sulphate for third final piece of silk. (for khaki colour) Silk must not be exposed too long to iron mix as can weaken it. Colour change is immediate so 5 mins sufficient; less to just dull colour.
Silk dyed with no mordant = GOLD.
Silk modified after dyeing with iron = KHAKI
Notebook: I bought the iron (ferrous sulphate) specially, but you can make your own. I generally experiment with adding water from a jar of rusty nails and screws; about half a tea cup to turn grey or khaki. Top up jar as rusty liquid is used. Even a spoonful dulls a colour adequately
[Note: Post restructuring: additional dye images being resized]