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Leafy Spurge - flower
credit: H. Zell/CCSA

Intruder in the West

It's a monster, plain and simple, that sneaks into areas unnoticed and within no time suffocates or muscles out the natives. And even if we like its appearance, the intruder warrants our ill will.

A bluish-green wildflower from Eurasia, Leafy Spurge most likely arrived here in seed form as part of some contaminated grain shipments. It was first noticed in New England during the early 1800s, and it showed up repeatedly across the continent as settlers spread west in the nineteenth century.

A remarkably adaptive and opportunistic species, Leafy Spurge flourishes in most types of soil from the subtropics to the subarctic. It spreads naturally by seed and vegetative growth and with help from birds and insects. Humans lend a hand, too, since the plant's roots and seeds stick to vehicles and farm equipment. Grain and hay shipments further broadcast the Leafy Spurge seeds.

And what makes it so unwelcome? Well, aside from the fact that it overwhelms native species, animals refuse to eat the plant. Deer, elk, horses, and cattle have benefited from some alien weeds, including many nutritious clover species deliberately introduced. The clovers grow like wildfire, of course, but animals keep them in check. Leafy Spurge, on the other hand, oozes with an unpalatable and toxic milky sap that wildlife and domestic creatures will have nothing to do with.

The result is that huge meadows in Montana and other places, once winter havens for ungulates and horses, are now overrun with spurge up to a thousand plants per square yard in certain areas. Ecologists and ranchers alike hope to find an answer.

But solutions are hard to come by. Leafy Spurge develops a very extensive root system and can grow plants quickly from even a fragment of root left behind from failed eradication efforts. Even flooding doesn't work given that spurge can survive up to four months underwater.

At present Leafy Spurge claims two-and-a-half million acres of the West. Unless botanists devise a new way of stopping its advance, there's no telling where it will stop.