Sunday, February 21, 2016

Bermuda Buttercups

Oxalis pes-caprae--the
crabgrass of Northern California.
   Sunday was a very nice day--mid-60s, low humidity, lots of sunshine--so I spent part of the day pulling more weeds from my perennial bed and along the retaining walls. It's nice to see the yard start to wake up after a cold December and a wet January: the currant bush is starting to put out leaves, and my very confused purple irises (they've been in bloom since Halloween) are about to be joined by my "fancy" irises.
   The main weed I pull at this time of year is the crabgrass of the Bay Area, Oxalis pes-caprae. It has a lot of different names: Bermuda buttercup, Bermuda sorrel, African wood-sorrel, Cape sorrel, buttercup oxalis, sourgrass, English weed, and a bunch of names that can't be repeated. I've used a few of those, but around here it's usually referred to as "that damned oxalis."
   This is not your average wood sorrel. I have clumps of wood sorrel in shady spots all over the yard and I like its tiny pink and white flowers and tidy behavior. I've grown up with wood sorrel (we always called it "shamrocks"), and I love to chew on the stems for their sour, lemony flavor.
My yard is not this bad, but it's close.
   Bermuda buttercups start to show up during the dark, cold, days of December, when nobody wants to be outside pulling weeds, then explodes across the landscaping in January and February. It's everywhere: popping up in verdant lawns; covering bare ground where nothing is planted; even growing up between cracks in walks and walls. As soon as it gets a little sun, the plants send out tall stems with a tuft of yellow flowers at the end. The floral spectacular lasts about six weeks, then the plants die back to the ground, leaving a mess that has to be pulled up and raked away.
   Nothing kills Bermuda buttercups. I know this--I've tried everything from pre-emergent herbicides to chemical defoliants, and the blasted stuff just comes right back for more. I think it probably would withstand nuclear attack. It's particularly insidious because it propagates in two different ways. When conditions are right, and the plant is pollinated, it will produce large, brown, seeds that end up everywhere (I think the plant may shoot them across the yard). However, seeds are not Bermuda buttercups' regular method of spreading: the plants produce hundreds of tiny, peanut-sized, bulbs that become new plants that each produce hundreds of tiny, peanut-sized, bulbs. The plants force their roots--and bulbs--deep into the soil, so even when the plant is pulled up, the bulbs stay in the ground. As a result, I have Bermuda buttercups everywhere: front yard, back yard, in potted plants and raised beds that have nothing but purchased potting soil.
   I do not like Bermuda buttercups. I can, however, tolerate plants that are useful, and it turns out "that damned oxalis" has a couple of uses. The first one is in salads. When the yard is full of plants, I'll pull a handful or two of leafy stems, give them a good rinse, and strip the leaves for the salad bowl. It adds a bright, lemony, note to the salad.
   The second use is that it's a dye plant. Ida Grae, in her book Nature's Colors, described it as a dye plant, but a previous attempt didn't produce any results. I tried again last week: I don't know if earlier in the season is better, or the water pH was different, but this time, it worked. I mordanted 250g of yarns with 10% alum and 5% cream of tartar, then simmered the yarns for about 45 minutes in a dye liquor made of 250g of Bermuda buttercup flowers and a gallon of tap water. I got a cool yellow on some handspun llanwenog, and a brighter yellow on the wool/nylon sock yarn.
Gold, yellow, and cool yellow--
all from the same dye pot.
   The big surprise came when I change the pH of the water the yarn was in. I set one skein of sock yarn aside, then soaked it in a "push" bath of 1/4-cup household ammonia in a gallon of water for about 15 minutes. That was all it took to turn the yarn a gorgeous gold.
   All in all, I'm pretty pleased with the results of my first experiments with Bermuda buttercups. I picked another 185g as I was pulling weeds: 100g are spread on a cookie sheet to dry, while the other 85g were packed into a ZipLoc bag and tossed in the freezer. I want to see if the color will still hold through being dried or frozen. If it does, I'll be able to pick, dry, and store the flowers until my regular dyeing sessions during the summer. Who knows? I might start to like Bermuda buttercups.

On the loom: Still threading heddles for the upholstery fabric.

On the needles: Bit of Magic scarf out of Plymouth Happy Feet; Number 27 socks, out of ice-dyed Valley Franklin sock yarn.

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