Canadian horseweed
Prepared by Jennifer L. D’Appollonio, Assistant Scientist, University of Maine, Orono, ME 04469. Updated February 2018.
Scientific name: Conyza canadensis (L.) Cronquist; also Erigeron canadensis L.
Common name(s): Canadian horseweed, horseweed, Canadian fleabane, Canada fleabane, coltstail, marestail, butterweed
Links: USDA PLANTS Profile, Go Botany
Images: (to see enlargements [PC]: click on image, then right click and choose “view image”)
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- July
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- pre-flower, mid-July
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- early flower, mid-July
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- flower detail
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- leaf detail
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- underside of leaves
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- mid-August
Description:
-annual
-native North American plant
-seeds can germinate late summer – early fall or in the spring
-produces lots of seeds
-inhabits a wide range of growing and cultivation conditions
- drought and water logged conditions
Management:
-very herbicide resistant
-resistant to roundup
-can be managed by
- thick mulch layer
- hand pulling
- continued mowing
- post emergent herbicides
Sources:
Boggs, Joe, and Joe. “THE WEEKLY WEED: Canadian Horseweed (Conyza Canadensis).” BYGL, 2016, bygl.osu.edu/node/534.