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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, 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. — K4, WV; Erigeron canadensis L. Basionym: Erigeron canadensis L. 1753

Links to other floras: < Conyza canadensis - FNA20

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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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image of plant© Gary P. Fleming | Original Image ⭷
image of plant© Aidan Campos source | Original Image ⭷
image of plant© Erik Danielson source | Original Image ⭷
image of plant© Gary P. Fleming | Original Image ⭷
image of plant© Erik Danielson source | Original Image ⭷
image of plant© Aidan Campos source | Original Image ⭷
image of plant© Gary P. Fleming | Original Image ⭷
image of plant© Joey Shaw source | Original Image ⭷

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Horticultural Information

NCBG trait

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:



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