Nature Notebook – Cow Vetch

The purple flower blooming now in fields and on roadsides, cow vetch, is a bit of a “good news, bad news” plant.

The good news part is that cow vetch is a member of the legume family. Its roots harbor bacteria that perform an essential fertilizing service. These bacteria capture nitrogen that is dissolved in the soil in an unusable, gaseous form and convert it into a form that be used as plants as a vital nutrient. The bacteria also hang out in peas, beans, clover and peanuts. Because of this nutritive storehouse, vetch has been grown for animal forage or as a fertilizing cover crop.

On the bad news side, vetch is a weak-stemmed invasive of gardens. It uses tendrils to climb over or up stronger plants so that it can get its leaves up in the sunlight. Once established, vetch is such a vigorous grower it can smother the vegetation under it. It spreads underground and produces seedpods that “explode” their contents throughout the growing area. The seeds are quite dense so they eventually fall through vegetation to the ground.