Published in the Contra Costa Times on October 15, 2005

Q. I have a big problem with a weed called Velvetleaf.

A. Velvetleaf is a large annual weed native to southern Asia, but well-adapted to most of California. It is tolerant to several widely used herbicides, and because of this is becoming a larger pest in annual beds, roadsides and ditches. The botanical name is Abutilon theophrasti. Other common names are Indian mallow, piemarket, cottonweed and butterprint. It is a relative of cotton and hollyhocks.

Velvetleaf is an annual, sprouting readily from seeds that can germinate throughout the growing season. The plant at maturity is 3 ½ to 7 inches with many branches supporting large round obcordate leaves covered with soft hairs. The stalks are also covered with short soft hairs, hence the common name. This plant is soft to touch, but has an unpleasant odor if crushed, which makes hand weeding more difficult. The leaves are 4 to 8 inches across and pointed at the tip. The flowers bloom starting in early summer and continue through fall with bright yellow, five-petaled flowers borne singly or in groups.

The seed capsules are disk-like circles with 9 to 15 seedcases (called carpels) , each ending in a point that is easily caught in animal fir, equipment or socks. Each carpel contains two or three seeds. A mature Velvetleaf plant can produce up to 200 capsules. The seeds are kidney-shaped and dark grayish brown, and can remain viable in the soil for more than 50 years. This plant does best in full sun, but can produce abundant seeds growing in part-shade. It is very difficult to control once it is established, so prevention is very important.

There are no biological control agents currently available for Velvetleaf. If you have a yard where the plants have been able to grow and set seeds for several years, you have limited options. Shallow cultivation three weeks after the seedlings emerge is particularly effective, although newer seeds are brought to the surface and will germinatedf, necessitating repeated hoeing.

A list of herbicides that are effective can be downloaded from the WeedRIC site at http://wric.ucdavis.edu.