I am fully taking advantage of my summer holiday at home and experimenting with new to me plants. St Johns-wort (hypericum perforatum) is one of these and what a fantastic little flower. According to Jenny Dean’s Wild Colour; four colours can be extracted in one dye bath! I went on to try this with some success
First I collected 80g of blooms (with some leaves) and simmered these until the dye liquid turned red. Then I added a 10g sample of unmordanted wool/bamboo as well as alum mordanted silk. Both started going red so I left them in for 10 minutes for the colour to deepen before removing from the dye bath.
Wool/bamboo – no mordant and silk mordanted with alum; dyed with blooms
Afterwards I added in a 20 g skein of alum mordanted merino/nylon which took on a brownish colour quite quickly, as did the skein that followed. I left the second skein in the bath overnight and modified both the next day with iron water for an olive green shade as I wasn’t particularly exited about the brown shades.
Alum mordanted merino/nylon dyed with St Johns-wort blooms + iron
Next bath I prepared, I dyed with the whole plant. I collected 100g of St Johns Wort and chopped it up to the dye pot. I simmered the bath for about 15 minutes until the dye liquid turned red again and then added in a 100 g skein of alum mordanted wool/bamboo. I left it for a simmer for 20 minutes and watched it turn a beautiful shade of green. I took the skein out and left it to cool overnight.
1st and 2nd bath – wool/bamboo mordanted with alum
L-R: silk dyed with only blooms and silk dyed with whole plant
I added in more yarn to this dye bath; another 100g skein of wool/bamboo and some silk fabric and then left these in the dyebath overnight after simmering for 15 minutes. They both dyed a very similar green as the first dye bath.
So out of the four possible colours, I managed three; reddish, green and brown. The green kept on giving and the last few dye baths I only added in small mini skeins as the dye liquid started loosing its colour. It never gave me any yellows. The PH in all baths was neutral and I used rain water for dyeing. I wonder how St Johns Wort would work dried as Im tempted to take some with me to continue experimenting.
Town Dyer 
Hi!
I’m pretty certain that this info is on this blog, but I can’t find it. When you say you used « alum mordanted » yarn, how do you do this? You pre-soak the yarn in an alum bath? What are the proportions? For how long?
Don’t hesitate to simply point mo to the right post. 🙂
Thank you so much!
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Hello! I pre mordant with 10 % alum of the weight of the fibres I want to dye. I usually do this in a separate dye bath; I heat the water and dissolve the alum in the bath and then add my fibres and simmer in 80 degrees for about an hour
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Thank you very much! I’ll try it this weekend! So exciting!
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