Thistles

Thistles are my nemesis here in Taos. There are four species of invasive thistle reported here. Native species include perennial grasses, a sedge and a rush, clover and goldenpeas, yarrow, cinquefoil, gentians, and licorice. River bottoms that have been overgrazed for generations (such as Valverde Commons) have very little native ground cover.The Russian Thistle (Salsola kali, or Kali tragus) becomes a ‘tumbleweed’. I have not tackled that one yet.

Canadian Thistle (Cirsium arvense) reproduces from roots and is very difficult to control. We have been mowing, and I have used a string trimmer along the fence lines, around houses, and along the road edges. It is located in New Mexico mostly along the Rio Grande. I have not positively identified my nemesis, and it doesn't help that Google Sites will not display portrait-oriented photos correctly.Bull Thistle (Cirsium vulgare) is a biennial that spreads only by seed. The bees love it. I have been chopping off the basal rosette of leaves that shades all competition up to a foot away from its taproot, but by now they are over three feet tall and very spiny. The one-inch diameter stem is quite woody and requires a sharp tool to cut. The spines pierce my leather gloves.

Carduus nutans (also known as Musk thistle or Nodding thistle) appears very similar and is also distributed in Taos County.

Cultivation will kill the Bull thistle by cutting the taproot, but will spread the Canadian thistle by distributing root fragments that sprout anew. So we don’t cultivate any longer. The community has one full-size tractor with a rotary mower attachment, a riding mower, two brush hogs, and a walk-behind mower, as well as two electric string trimmers and one gasoline string trimmer. We no longer have to wait for a commercial mower to come when called.