Common burdock Arctium minus
IDENTIFICATION — If you’ve ever walked through a patch of weeds and come out with spiky brown balls stuck to your clothing, you’ve found common burdock. This biennial spreads by seed. The first year it makes a low rosette of coarse, pale green leaves. In spring of the second year, the rosette beings to stretch, and by summer, the branched flowering stalk can be 5 ft. tall. Rosy purple flowers bloom in summer and are followed by ¾-in. fuzzy brown seed clusters, or burrs.
FAVORITE CONDITIONS — This very adaptable weed can be found in much of the United States and Canada. It’ll grow in full sun or shade, rich soil or poor — it’s not picky. Since it takes two years to produce seed, common burdock likes areas that are undisturbed.
CONTROL — Cultivating will kill common burdock seedlings. When you spot flower stems starting to stretch, cut the plant off at the base with a sharp spade. Root pieces in the soil will grow back, so repeat this process until the plant dies. If flower heads have turned brown, they’ve set seeds and need to be cut off and thrown away in the trash.
You can use herbicides to control common burdock. In lawns, a broadleaf herbicide containing 2, 4-D, is effective and won’t harm the grass. Non-selective weed killers, like Roundup®, are fine where you don’t mind getting rid of everything.