Burclover

How can a clover be a weed? Is it all bad? Let’s find out!

California burclover (Medicago polymorpha) is an invasive annual weed that looks a lot like other clovers. The name polymorpha refers to the fact that the burrs can be smooth or snaggish. As far as weeds go, this one isn’t entirely bad. Also known as burr medic, bur trefoil, and creeping burr, this weed actually has a lot going for it.

CA burclover (Ixitixel) CC BY-SA 3.0

Cousin to white clover, black medic, and strawberry clover, California burclover is sometimes grown on purpose to feed livestock. Being an annual, however, it will leave bare patches in your lawn, come summer. Also, those little burrs can wad themselves up on your favorite sweater and they are not particularly fun to step on barefooted. While some burrs are smooth, most of them feature rows of tiny velcro-like hooks that snag. Like other weeds, the best time to pull them out is when they are small and young, before they go to seed.

​California burclover identification

Seed leaves (cotyledons) are oblong. The first set of true leaves are rounded. Mature burclover leaves look like they fold in the middle and are three round leaflets. They may have reddish midveins and toothed margins. Stems can reach 2 feet long and tend to trail, but may be upright, and they break easily. Small yellow flowers form in clusters at the end of stems. The seed pod is either smooth or a prickly burr that sticks to pet paws and fur, shoes, clothes, and enough other things that this pesky weed can easily be brought into your garden or landscape after a stroll around the block. These burrs look as though they are twisted on themselves. They start out green and then turn brown and hard. While these prickly burrs can get tangled in your pet’s fur, they are not the “stinging” “life threatening” weeds sensationalist articles claim. We will leave those claims to the foxtails.

Green burclover burr (Harry Rose) CC BY 2.0

The good side of burclover

In addition to being grown as livestock and chicken food, California burclover is also used as a ground cover, winter erosion control, green manure, and in soil restoration. A drought tolerant legume that thrives on slightly alkaline soil, burclover requires very little water and it grows rapidly into a dense vegetative cover that adds nitrogen to the soil. A single acre of burclover can produce 8300 lbs. of biomass in a single season! In many areas of the world, burclover is rotated in pastures with cereal grains for a continuous supply of healthy food for livestock. If you were/are a farmer growing hay for livestock, adding burclover to your oats and wheat can increase production by 3 to 5 times.

But you probably see burclover as a weed in your lawn, as I do. Now that I know burclover is also a nutritious legume, I will feel better about feeding those weeds to my chickens.