The tomatoes in the bottom of the screen will draw your eye, but the plant I am asking you to look at is in front of the tomatoes. I'm showing you the whole photo so that you can see the scale of the whole plant.
It is Polygonum persicarium, also known as Lady's Finger or Lady's Thumb - or Redshank, or Smartweed.
Here's a zoom into the flower.
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And here's a zoom into the leaf and stem nodes. You can see why it is called "Redshank."
If you live anywhere near the Midwestern US, I am sure you have seen this plant as a weed in your garden.
It is actually edible, as long as you use it moderately. It has oxalic acid in the leaves, which can be a problem for those with kidney stones. I hadn't seen it recommended for use as a dye plant, but I was curious.
It is in the buckwheat family. Smartweeds and knotweeds belong to this family. I was interested in its use as a dye plant, because I have ordered and received seeds for another buckwheat family member, Japanese Indigo (Persicaria tinctorium, previously Polygonum tinctorium). It's the wrong time of year to plant them, but I have every intention of planting them next spring. The plant photos I have seen look fairly similar to smartweed, but smartweed is an annual and Japanese indigo is a biennial, with a rosette of leaves in the first year and flowers in the second. Japanese indigo is also known as Dyer's Knotweed. Indigo dye can be extracted from the leaves of Dyer's knotweed.
There is also another non-native, invasive plant in the same family, which has a similar name. That would be Japanese Knotweed (Polygonum cuspidatum or Renoutria japonica). It is a major threat in areas along waterways. In my Master Gardener class earlier this year, my group did a presentation on control of Japanese Knotweed. It is not easy, as the plant spreads by rhizomes, by stem cuttings, and prolific seeds. It crowds out other native plants and destroys habitat. Maybe another day I will try it out as a dye plant. I noticed a stand out by the Malabar Farm horse camp.
In the meantime, I have plenty of smartweed in my tomato garden that is not supposed to be there. So the other day I gathered a bunch of it and put it in a dyepot. I experimented with the technique of mordanting the fiber at the same time as dyeing it. In other words, after cooking the plant for an hour, I strained out the leaves and stems and added the iron mordant to the dye pot before adding the dry fiber. (I was in a time crunch, I had lots of stuff to do before leaving to attend the dye class up in Northfield.)
I brought the pot back to a simmer for about an hour, then turned it off and left the fiber in the dyepot overnight. The next morning, I did not have time to deal with it, so left it again until I returned home on Thursday night. I pulled out the fibers and rinsed them, then left them to dry.
The color appears greenish-grey. Iron mordant will "sadden" any color, so it is contributing the grey color. It appears different under different lighting conditions.
You will notice the twistiness of the fibers. I'm not sure if I shocked the wool by raising the temperature too fast. The yarn is from Made In America yarns. It's a single-ply and did not have these twisties before I simmered the yarn. I bought "Big Superwash Wool" which is 3 or more pounds of 80% merino and 20% nylon. It arrived in two cones. The two cones seem to be somewhat different - this one is a single ply and the other appears to be a multiple-ply yarn, although they are both sock weight. Or maybe I mislabeled them and this is the alpaca I ordered in the same batch?
This is a question that needs resolution. Guess I have some work cut out for me. In the meantime, there is still a lot of pigment that was not exhausted in the first dye bath, so I will be doing a second skein to exhaust the color or any remaining mordant. I'll take the opportunity to look at the fiber again.
In the meantime, I just stumbled across
a web page from Brandeis University that does mention smartweed as a dye plant. However, it does not distinguish between the several different species of smartweed and knotweed. The "
Wild Colors" website does discuss Japanese Indigo cultivation and use as a dye plant,
