Creeping

Creeping Thistle (Cirsium arvense)

As I mentioned a few weeks ago, we've been doing battle with thistles in the garden since moving in two and a half years ago. So far, it's a battle we're losing! While some of our foes are the big (and prickly) Spear Thistles, by far the larger number are the tenacious, perennial Creeping Thistles (Cirsium arvense). These plants are somewhat smaller and less robust than their Spear Thistle cousins, with smaller, paler pink flowerheads. The capitula (the wine glass shaped purple bit under the flowers) isn't as viciously spiked as is the capitula on the Spear Thistle, though the rest of the plant is certainly well protected with sharp spines. Unlike the Spear Thistle, which spreads only by seed, this one spreads by underground runners as well — and that makes it very hard to eliminate. The roots break easily into sections when we try to pull them up, and sections as small as 1/4-inch (3mm) can grow into a new plant. I expect we'll still be grubbing bits up in 20 years. Its propensity to regenerate from root fragments, and its ability to produce upwards of 5300 seeds per plant (and for those seeds to remain viable for as long as 20 years) makes Creeping Thistle a real problem for farmers. And since it has been accidentally introduced from its native Europe across much of the globe, it's impact is being felt worldwide. In many places, including its native range, it's considered to be invasive. However, from a wildlife point of view, it's not all bad news. Its seeds are an important food source for farmland birds, which are rapidly declining across Europe. European Goldfinches and Linnets are said particularly fond of them, and the two pairs of goldfinches we've had nesting in the garden this summer may have been at least partly attracted by them. The flowers are visited by a host of pollinators, and the foliage is the larval food for at least 20 species of butterflies and moths, including the Painted Lady. We will need to be vigilant though, if we don't want it to take over the rest of the garden.