Questions on: Common Mallow
Ron Smith, Horticulturist, NDSU Extension Service
Q: I have a mystery plant in my garden. It appears to be some kind of sunflower. Last year I had an herb garden in the spot where this has grown. It was over five feet tall and many seed heads have grown. (Regent, N.D.)
A: Your mystery plant is called velvetleaf (Abutilon theophrasti) and is a member of the Mallow family. The seed can remain viable in the soil for 50 years, so it is good you pulled this one before it was able to disperse its load of seed. Heights of 6-8 feet are not uncommon. Some folks use the dried seed pods (or fruits) in dried floral arrangements. The plant becomes more noticeable in farm fields and gardens as the summer heat accumulates.
A: Ah, the pervasiveness of weeds! A seed can get in anywhere as a contaminant, which it obviously has done in your case. As far as weeds go, the mallow is not too bad. It actually has a nice flower, for a weed. It is not invasive, and I know of no allergic reactions to it. Potting soil companies usually pasteurize their soil, or use non-soil components to avoid weed seed, insect, and disease problems. In this case, this weed seed survived, and is responding to the TLC you are providing.
Q: A weed that we have identified as common mallow is taking over our lawn this summer. I would like to know how to eliminate it. (Bowdle, S.D.)
A: Common mallow does not take over lawns, but ground ivy (Glechoma hederacea) does. The two are similar in appearance, but strikingly different in many other ways. Mallow is an annual while ground ivy is a perennial; mallow does not root at the nodes while ground ivy does; mallow is easily controlled while ground ivy requires persistence to eliminate. I suggest repeat applications of Trimec--now and again in September. That should take care of most of it, with some touch-ups in the spring.
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