Conyza canadensis (L.) Cronquist
Horseweed, Canadian Horseweed
Asteraceae (Aster Family)
USDA Symbol: COCA5
A coarse weed with erect bristly-haired stem that has branching
Conyza canadensis (L.) Cronquist
Horseweed, Canadian Horseweed
Asteraceae (Aster Family)
USDA Symbol: COCA5
A coarse weed with erect bristly-haired stem that has branching clusters of small, cup-like, greenish-white flower heads arising from upper leaf axils. The minute white rays do not spread and thus are not showy; the numerous disk flowers are yellow.
An annual that thrives on bare soil, Horseweed is soon crowded out as perennials become established. Originally a North American plant, it has spread to Europe, where it colonizes open disturbed sites. Indians and early settlers used a preparation of its leaves to treat dysentery and sore throat.
From the Image Gallery
Bloom InformationBloom Color: White
Bloom Time: Jul, Aug, Sep, Oct, Nov
DistributionUSA: AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY
Canada: AB, BC, MB, NB, NL, NS, NT, ON, PE, QC, SK
Native Distribution: Throughout North America, except parts of far north.
Native Habitat: Fields, roadsides, and waste places.
Growing ConditionsWater Use: Medium
Light Requirement: Sun
CaCO3 Tolerance: Low
BenefitConspicuous Flowers: yes
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Pineywoods Native Plant Center - Nacogdoches, TX
Sibley Nature Center - Midland, TX
Brackenridge Field Laboratory - Austin, TX
Stengl Biological Research Station - Smithville, TX
Wildflower Center Seed BankLBJWC-0148 Collected 2007-09-04 in Travis County by Lady Bird Johnson Wildflower Center
Additional resourcesUSDA: Find Conyza canadensis in USDA Plants
FNA: Find Conyza canadensis in the Flora of North America (if available)
Google: Search Google for Conyza canadensis
MetadataRecord Modified: 2016-07-14
Research By: TWC Staff