Most thistle species are a nuisance

Published 5:32 am Saturday, August 19, 2023

If you own much land, chances are it has thistle growing on it. This group of plants is one of the most persistent weeds in our area, and if dirt is exposed it will likely end up growing there.

There are several thistle varieties in our area, and the most troublesome ones are from Europe. All grow to be 3-5 feet tall and have thorny leaves that are painful to brush against. Their showy purple blooms appear in late July through September, have a shaving-brush appearance. The most common thistles we have include Canada Thistle (actually from Europe), and Field thistle, a native.

Both plants are biennial, taking two years to produce seed and complete their reproductive cycle. The first year they are small and form a rosette of leaves that hug the ground. The second year they send up a flower stalk and bloom. Seed are produced in pods that burst open, releasing seeds on feathery parachutes that carry by wind for long distances. If you have a lot of thistles on your property, your neighbors may not appreciate it.

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For farmers thistle is a problem in pastures, as cattle won’t eat it. Goats, sheep, and donkeys seem to like it, and I know of one person who keeps a donkey with his cattle specifically to control thistle. Grazing a mixture of livestock species can reduce weed problems, as does rotational grazing, which gives sections of pasture grass a chance to rest and stay healthy and thick. Herbicides will control thistle, but always use caution and follow label directions to the letter.

Thistle does provide food for the goldfinch, sparrows, and hummingbirds. Humans have eaten the young leaves raw or cooked, the young stems peeled and eaten raw or cooked, and the roots of first year plants. If you’re so inclined, remember to eat only a small portion of any new food in case of food allergies, and be sure to positively identify the plant. Thistle has some medicinal history, having been used as a diuretic, for dysentery, and diarrhea. Also used externally to treat poison ivy rash and skin ulcers.

Steve Roark is a volunteer at Cumberland Gap National Historical Park.