Velvetleaf (Abutilon theophrasti) is an aggressive annual weed that is throughout the United States, and a significant weed of corn and soybean production. The plant thrives in nutrient-rich soils and competes aggressively with crops for nutrients. Velvetleaf seeds can persist for decades, so preventing seed set is important for this species. This species may overwinter in Zone 8 or warmer climates.
Mature Velvetleaf plant leaves
photo by Howard F. Schwartz via Colorado State University, Bugwood.org
Identification
Seedlings: Cotylesons are 1/10-1/2″ (.3-1.3 cm) long, often one rounded and the other heart-shaped, and softly hairy (leaf stem); the first-emerging stem, beneath the cotyledons and leaves, is short, round in cross-section, densely hairy, and green or dark red at the base. First true leaves are alternate, heart-shaped, densely hairy, and angled downward with the tips pointed toward the ground.
Velvetleaf cotyledons
Photo by Bruce Ackley of the Ohio State University, via Bugwood.org.
Velvetleaf seedling
Photo by Steve Dewey via Utah State University, Bugwood.org
Leaves: Leaves of the mature plant are alternate and large (5-7″/10-15cm long and wide), with a petiole about as long as the leaf. They are densely hairy, very soft (hence the common name velvetleaf), heart-shaped with a sharp tip and finely toothed margins, and have palmate (fanning out from the leaf base), branching veins.
Leaf of mature velvetleaf plant
photo by NY State IPM Program at Cornell University via flickr.com
Mature plants: Mature plants can grow up to 7′ tall; stems of the mature plant are upright, densely hairy, and often branching towards the top. The root system is fibrous with a shallow, branching taproot. Leaves and stem have an unpleasant smell when crushed.
Mature Velvetleaf plant
photo by Charles T. Bryson via USDA Agricultural Research Service, Bugwood.org
Flowers/Fruits: Flowers emerge at leaf axils from July – August. They are up to 1″ (2.5 cm) wide, with five yellow to orange petals. The fruit is a distinctive, cup-shaped disk composed of 9-15 pointy-tipped sections. Three to nine brown, heart-shaped seeds are held in each section. These seeds can persist up to 50 years in the soil.
Velvetleaf yellow flower and immature fruit
photo by Joseph M. DiTomaso via University of Californai- Davis, Bugwood.org
Management
Chemical control
For management in New York agricultural situations, please refer to the Cornell Crop and Pest Management Guidelines. You can also find chemical control information at Cornell University’s Turfgrass and Landscape Weed ID app.
Non-chemical control
As most velvetleaf emerge in the spring , delayed planting or rotating to a summer crop can eliminate seedlings through tillage. Since velvetleaf does not set seeds until late summer, early harvest crops such as winter/spring small grains also work well to interrupt its life cycle.
Tine weeding or rotary hoeing can be effective if conducted at the white thread stage (just emerging seedlings). Shallow cultivation just below or at the soil surface that cuts the plant’s stem can be effective against larger seedlings.
Seeds left on the soil surface are vulnerable to predation and dessication, so delaying fall tillage in fields with a lot of velvetleaf seed production can reduce the number of seeds that wind up in the seed bank.
Although velvetleaf is capable of emerging through thick layers of mulch material, the weed has been successfully be suppressed when soybeans are sowed into a no-till rye cover crop.
Velvetleaf seeds are resistant to heat, so solarization is not an effective management strategy for this species.
Climate Change and Management
Velvetleaf grows larger and self-thins more under elevated CO2 levels and higher temperatures, increasing its competitiveness. In corn, velvetleaf becomes less competitive under high temperatures and low soil moisture, likely due to corn’s C4 metabolism which reduces drought stress (link to a C3/C4 worksheet). In sorghum, velvetleaf significantly reduces crop yield under elevated CO2.
References
Uva R H, Neal J C, DiTomaso J M. 1997. Weeds of the Northeast. Book published by Cornell University, Ithaca NY. The go-to for weed ID in the Northeast; look for a new edition sometime in 2019.
Cornell University’s Turfgrass and Landscape Weed ID app. Identification and control options for weeds common to turf, agriculture, and gardens in New York; uses a very simple decision tree to identify your weed.
The non-chemical management section of this page is based on information from Chuck Mohler of Cornell University. Look for Manage Weeds on Your Farm: A Guide to Ecological Strategies, an upcoming book from the Sustainable Agriculture Research and Education (SARE) by Charles (Chuck) Mohler, John Teasdale, and Antonio DiTommaso.
The University of Wisconsin-Madison’s Horticulture extension program has a good velvetleaf profile, with a thoughtful discussion of seed longevity and predation.
Michigan State University’s Department of Plant, Soil and Microbial Sciences has an extension page for velvetleaf, including detailed discussion of chemical, biological, and cultural management options.
University of Missouri’s Weed ID Guide: Velvetleaf. The Mizzou Weed Guide is a great resource for weed identification information and clear photos of plant traits.
Edler, B. et al. (2015) ‘Growth responses to elevated temperature and reduced soil moisture during early establishment of three annual weeds in four soil types’, Journal of Plant Diseases and Protection, 122(1), pp. 39–48. doi:10.1007/bf03356529.
Morse, S.R. and Bazzaz, F.A. (1994) ‘Elevated CO2 and temperature alter recruitment and size hierarchies in C3 and C4 annuals’, Ecology, 75(4), pp. 966–975. doi:10.2307/1939420.
Ziska, L. (2012) ‘Observed changes in Soyabean growth and seed yield from abutilon theophrasti competition as a function of carbon dioxide concentration’, Weed Research, 53(2), pp. 140–145. doi:10.1111/wre.12005.
Ziska, L.H. (2003) ‘Evaluation of yield loss in field sorghum from a C3and C4weed with increasing CO2’, Weed Science, 51(6), pp. 914–918. doi:10.1614/ws-03-002r.