Purple Crown Vetch vs American Vetch
I’ve had this plant volunteer in several of my gardens. It’s quite attractive, as the purple flowers bloom summer-long. But it turns out that Purple Crown Vetch is a very aggressive invasive species. It can be widely found in Maryland in sunny, open places, such as unmowed fields or along roads. I know I’ve seen it in many places.
The plant itself was imported from Eurasia in the 1950’s to control erosion. It’s actually quite effective, even over the winter.
It has ferny vine-like stems and leaves and the flowers look a lot like red clover flowers. It can climb a foot or two high if given support. Without support, it tends to be a bushy pile around 10 inches high. It’s a (non human-edible) legume and spreads by rhizomes. It absolutely will smother everything in its path, even other aggressive ground covers. I suspect it would lose in a fight against Kudzu, though.
It is considered a serious ecological threat. It out competes native equivalents, such as American Vetch, which is actually considered endangered in Maryland. Purple Crown Vetch can even climb over and smother small shrubs.
Interestingly, the funny-sounding word vetch is an old English word. It dates to the 14th century, and comes ultimately from Latin vicia, a form of the Latin vincere, to bind. Purple Crown Vetch certainly binds everything in its path!
Now that I’ve learned how problematic this invasive volunteer can be, I will be (painfully) eradicating it from my garden and replacing it with something else.