Erigeron canadensis Linnaeus. Common name: Common Horseweed. Phenology: Jun-Nov. Habitat: Old fields, disturbed areas, roadsides, gardens. Distribution: S. Canada south through nearly all of the United States to tropical America.
Origin/Endemic status: Native
Synonymy ⓘ: = F, Tat; = Conyza canadensis (L.) Cronquist var. canadensis – C, G, GrPl, Mo2, NcTx, Oh3, Pa, SE1, Va, W; = Erigeron canadensis L. var. canadensis – NY, RAB; = Leptilon canadense (L.) Britton – S; = Leptolon canadensis (L.) Britton; < Conyza canadensis (L.) Cronquist – Ar, Fl7, FNA20, Il, K2, Mex, Mi, NE, Ok, Tn, WH3; > Conyza canadensis (L.) Cronquist var. canadensis – Tx; > Conyza canadensis (L.) Cronquist var. glabrata (A.Gray) Cronquist – GrPl, Tx; < Erigeron canadensis L. – K3, K4, WV
Links to other floras: < Conyza canadensis - FNA20
Wetland Indicator Status:
- Atlantic and Gulf Coastal Plain: FACU (taxonomic split from wetland indicator species)
- Eastern Mountains and Piedmont: FACU (taxonomic split from wetland indicator species)
- Great Plains: FACU (taxonomic split from wetland indicator species)
- Midwest: FACU (taxonomic split from wetland indicator species)
- Northcentral & Northeast: FACU (taxonomic split from wetland indicator species)
Heliophily ⓘ: 8
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Horticultural Information
Intro: Erect, bushy annual of fields, gardens, roadsides and other open, disturbed areas.
Stems: Stems branched above the middle, hairy or smooth.
Leaves: Leaves alternate, narrowly lance-shaped, 3/4-4 in. long, margins entire or toothed and fringed with small hairs.
Inforescence:
Flowers: Composite flowers (heads) on wide-spreading branches of upper 1/3-1/2 of plant; heads about 1/4 in. long, cylindric to urn-shaped and consisting of 20-45 tiny, white ray florets surrounding center disk of yellow tubular florets. Several series of narrow, green-tipped bracts surround the base of each head.
Fruits: Fruit a cluster of tiny flattened achenes with tufts of white or tan hairs.
Comments: The very similar Conyza canadensis var. pusilla has purple-tipped bracts surrounding the base of the flower head.
Height: to 6 ft.
plant sale text:
bloom table text:
description: Erect, bushy annual of fields, gardens, roadsides and other open, disturbed areas.
stems: Stems branched above the middle, hairy or smooth.
leaves: Leaves alternate, narrowly lance-shaped, 3/4-4 in. long, margins entire or toothed and fringed with small hairs.
inflorescence:
flowers: Composite flowers (heads) on wide-spreading branches of upper 1/3-1/2 of plant; heads about 1/4 in. long, cylindric to urn-shaped and consisting of 20-45 tiny, white ray florets surrounding center disk of yellow tubular florets. Several series of narrow, green-tipped bracts surround the base of each head.
fruits: Fruit a cluster of tiny flattened achenes with tufts of white or tan hairs.
comments: The very similar Conyza canadensis var. pusilla has purple-tipped bracts surrounding the base of the flower head.
cultural notes:
germination code:
native range: