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How to Manage Pests

Identification: Weed Photo Gallery

Horseweed

Scientific name: Conyza canadensis (Sunflower Family: Asteraceae)

Life stages of Horseweed top left picture bottom left picture right picture

Click on image to enlarge

DESCRIPTION:
Horseweed, also called mare's tail, is a summer annual or biennial broadleaf. If undisturbed, the plant grows erect, branching only near the top. Cotyledons (seed leaves) are oval with fine hairs. Leaves of young plants grow as a rosette around a crown. Later plants grow erect and an abundance of dark green leaves alternate along the stem. Small, yellowish flower heads are borne at the end of branched stems and are slightly larger than those of horseweed.Mature plants can reach up to 10 feet (3 m) tall. Shorter, mowed plants may look similar to hairy fleabane, but horseweed has dark green leaves while hairy fleabane has gray-green leaves. It competes severely for water and grows rapidly.

Broadleaf ID illustration.


Statewide IPM Program, Agriculture and Natural Resources, University of California
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For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See How to manage pests, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/WEEDS/horseweed.html revised: November 17, 2008. Contact webmaster.