A Case for Loving Thistle

Aug 19, 2019

When’s the last time you thought about a thistle as beneficial?

In this week’s Wildlife Matters, the Masked Biologist makes a case for loving the thistle.

When last we spoke, I talked about the American Goldfinch, and its notable relationship with thistles. Of all the seeds that goldfinches eat, thistle seeds are by far their favorite. Even if you are not a biologist, if you feed birds you probably know your best chance of seeing goldfinches is if you put out a thistle sock or thistle tube. Their relationship with thistles extends even further; they use copious amounts of thistle-down in their nests. These birds rely so heavily on thistles, it is thought, that they time their nesting when the thistles produce their downy seed to provide nesting material and food for themselves and their young.

Here’s the problem, though. Nobody loves thistles. Okay, Scottish people love thistles, but not many others. Sadly, if you look at the average thistle in a pasture or on the roadside today, it may well be a non-native species. Wisconsin does have a few species of native thistle, but they are on the way out because farmers, ranchers and lawn enthusiasts have declared war on thistles in general.

We should love thistles, though—especially our native thistles. When you were little, running barefoot through your lawn, and you stepped on a thistle that felt a little like one of those cartoon bear traps? That was probably a non-native thistle. Our native thistles have less large, stabby spiky thorns and almost more like coarse hairs over them. The more spiky thorns are far fewer and farther between.

Thistles produce some of the sweetest nectar and some seriously nutrient-packed pollen. Because of this, they are a preferred plant species for visits by pollinators like bees and butterflies. In fact, studies in other parts of the country have shown that our native species of what we refer to as long-tongues bees have a crucial relationship to our native thistles. That makes sense, right? They have co-existed together for unknown numbers of years before settlers changed the landscape and introduced thistle species from overseas in with their seed stocks and in and on their livestock.

Hummingbirds are also attracted to these plants, because of their sweet nutritious nectar. And, after the flowers are pollinated, they produce seeds that birds like goldfinches, sparrows, juncos and buntings go crazy over. The seeds are very small but are extremely dense and high in essential nutrients and oils. If you are a hobby birdfeeder, you may think of black oil sunflower seeds as a top choice for feeding, and you’d be right. In fact, thistles are related to sunflowers, in the same family, so they share a lot of similarities with their showy popular cousins. I know a few people who decorate kitchens with sunflowers, like my own wife, but I don’t know anyone who decorates a kitchen with thistles.

Finally, some of our ground-dwelling mammal species benefit from thistles, such as pocket gophers, thirteen lined ground squirrels, and moles. These may not be desirable species in terms of home lawn and garden management, but they are native rodents that play a critical role in the natural food chain, and many have been disappearing from our landscape.

The upshot here is that the thistle has gotten a bad rap. They may be kind of ugly and thorny, but they are sweet on the inside. Remind you of any people you know? I can certainly relate. I think I will see if I can track down a native thistle or two to introduce to one of my rain gardens and see if I can remind myself that its okay to be a thistle among sunflowers.

Striving to make new things familiar and familiar things new, this is the masked biologist coming to you from the heart of Wisconsin’s great Northwoods.