Buffalo bur: a plant that will really stick with you

By Gary Raham
Nature Writer and Illustrator

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Every time I see a bicyclist at the side of the road energetically trying to inflate a punctured tire, I think, "I bet they've discovered buffalo bur." Nearly every time I suffer a deflated bicycle tire--at least in Colorado--the cause is a brown seedpod with spines that a medieval knight would have been proud to put on his mace. That seed belongs to Solanum rostratum, alias horse nettle, alias buffalo bur.

One day I met the plant that produces the bur in my own garden. It's a weed with alternate, deeply lobed leaves that remind me a little of oak leaves. But not for long. Everything about the plant is spiny, from leaf petiole to stem to annoying seedpod. You will not pull this weed at the height of its yellow-flowered glory without heavy leather gloves.

But every weed, every bad seed, has its champion. A rather attractive striped beetle, Leptinotarsa decemlineata, prefers buffalo bur as its food of choice, its home and the nursery for its larvae and grandlarvae.

This is not to say that Leptinotarsa hasn't flirted with other homes and food sources. In fact, Leptinotarsa's common name is the Colorado potato beetle, a title it acquired in the 19th century when people began planting huge tracts of potatoes, a domesticated relative of the buffalo bur plants. Leptinotarsa jumped from its age-old, spiny partner to the abundant new plants, although it still preferred buffalo bur when it could find it. Buffalo bur, it seemed, was lacking an old association with the vanishing bison that once roamed huge areas of the Great Plains.

A naturalist named Thomas Say discovered buffalo bur while he was on the Long Expedition of 1819-1820. Yes, the expedition was named after the same Maj. Stephen H. Long who lent his name to Long's Peak. A great account of this expedition is given in Howard Ensign Evans' book, "The Natural History of the Long Expedition to the Rocky Mountains." Say discovered lots of buffalo bur near buffalo wallows, where the great beasts rolled and thrashed around in muddy water to cool off on long, hot afternoons. Undoubtedly, buffalo carried buffalo burs far and wide in their fur as they rambled along the Front Range. That job now falls to bicyclists, lost dogs and boys cavorting in weed fields.

Potato beetles became less of a pest for farmers as various insecticides were developed that had some effect, including Bt insecticides carrying bacterial endotoxins. However, judicious crop rotation works best. Adult potato beetles fly about as well as those tank analogues called Hummers, so they don't disperse well. They can also be enticed to raise their families on hairy nightshade, another weed in the potato family endemic to this area. Surprisingly, potato relatives like the nightshades and horse nettles are poisonous, containing various steroids, toxic alkaloids and glycosides that cause vomiting, vertigo, convulsions, weakened heart and paralysis in humans.

Of course, eating buffalo bur is probably the last thing on your mind.

I usually pride myself in finding value in all creatures, great and small. And buffalo bur certainly sets a sterling example of self-defense and clever seed dispersal. Nevertheless, I curse when a seed impales my bicycle tire and I smile every time I pull one of the plants out--very carefully, of course--by the roots.