Sourgrass also known as Common Yellow Woodsorrel or Oxalis Stricta.
Sourgrass flowers are a common sight here in Northern California in early spring. They pop up during the rains and stick around until the heat of early summer arrives. Sourgrass is native to North America and many people consider it an invasive weed. It grows wild here, especially in vacant lots, or in alleyways where I like to collect it from. If you have access to sourgrass flowers in the spring make sure to give this dye a try, it’s actually easier than making lemonade!
Sourgrass is edible and if you’ve ever nibbled on the stems and tasted their tart flavor then you know why they have their name. Sourgrass contains oxalic acid which gives it a sour taste and is a natural bleaching agent. Oxalis leaves, along with other leaves containing oxalic acid such as rhubarb and Virginia Creeper can be used to discharge dyes on fabrics. I plan to write a separate post about that in the future. For this post I’ll be focusing on the flowers of sourgrass, which make a beautiful strong yellow dye.
Sourgrass can be extracted using gentle heat but I find that the brightest color comes from dye that is extracted cold or at room temperature. I used a large glass container and filled it with as many sourgrass flowers as I had. I don’t usually measure or weigh anything when I dye. I use as much of the dyestuff as I have, and then I add just enough water to cover. If you want a deep color, or are dyeing a large amount of fabric make sure you have a lot of dyestuff, the more you have, the more dye pigment you will be able to extract.
I found through experimenting that the leaves and stems can be included or discarded, they make little impact on the color since all of the dye pigment seems to come from the flowers. I removed most of the stems to make room for more flowers, but you can include them if you wish. I covered the flowers with water and left the container to sit for about 36 hours. I could have strained the dye earlier, the color started to release after just an hour or two, but I wanted to be sure that all the pigment was extracted.
Once the flowers looked spent and the water was a vibrant yellow I strained the mixture through cotton gauze (cheesecloth works as well), and then returned the strained dye back to the container where I added my fabric samples (if there isn’t enough liquid for your fabric to move around freely add some more water at this point). I then let those sit in the dye for another 24 hours.
When I was happy with the color of the samples I strained the mixture again and let the samples dry. I used fabric that had been mordanted with alum and fabric that had been soaked in a soy milk binder to test the differences, as well as fabric that was not mordanted. You can see in the photo below the details of each fabric sample.
I love how sunny the results are. There is something about a fresh bright yellow that always
helps to lift my spirits. Sending you some beautiful bright yellow plant magic wherever you are!
A few notes:
You can place your container in the sun or not, I tried both ways and found the results very similar.
Add an alkaline element like baking soda or soda ash to shift the dye more toward an orange hue.
Save some dye in a jar and use as an ink on paper