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Native Plant Database

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Conyza canadensis (Canadian horseweed)
Schwartzman, Steven

Conyza canadensis (L.) Cronq.

Canadian horseweed, Horseweed

Asteraceae (Aster Family)

USDA Symbol: COCA5

USDA Native Status: Native to U.S.

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

Plant Characteristics

Duration: Annual
Habit: Herb
Leaf: Green
Flower:
Fruit:

Bloom Information

Bloom Color: White
Bloom Time: Jul , Aug , Sep , Oct , Nov

Distribution

USA: 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.
USDA Native Status: L48(N), AK (I?), HI(I), PR(N), VI(N), CAN(N), SPM(N)

Growing Conditions

Water Use: Medium
Light Requirement: Sun
CaCO3 Tolerance: Low

Benefit

Conspicuous Flowers: yes

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is either on display or available from the following:

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 Bank

LBJWC-0148 Collected 2007-09-04 in Travis County by Lady Bird Johnson Wildflower Center

Recommended Species Lists

Find native plant species by state. Each list contains commercially available species suitable for gardens and planned landscapes. Once you have selected a collection, you can browse the collection or search within it using the combination search.

View Recommended Species page

Additional resources

USDA: Find Conyza canadensis in USDA Plants
FNA: Find Conyza canadensis in the Flora of North America (if available)
Google: Search Google for Conyza canadensis

Metadata

Record Modified: 2009-09-26
Research By: TWC Staff

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