Canadian horseweed

(Erigeron canadensis)

Conservation Status
Canadian horseweed
  IUCN Red List

not listed


N5 - Secure

SNR - Unranked


not listed

Weed Status

Canadian horseweed is commonly considered a weed. It is a considerable agricultural pest in soybean fields. In 2001, it was reported that it developed resistance to the broad-spectrum herbicide glyphosate, sold by Monsanto under the name Roundup. Ohio is the only state to put it, under the name “marestail”, on their Prohibited Noxious Weeds list.

Wetland Indicator Status
  Great Plains

FACU - Facultative upland


FACU - Facultative upland

  Northcentral & Northeast

FACU - Facultative upland


The stem is unbranched below the inflorescence.

The leaves are linear and crowded on the stem.




12 to 60


Flower Color


White ray flowers, yellow disk flowers


Similar Species


When not in flower, the linear leaves are enough to identify this as Canadian horseweed and not a goldenrod.


Disturbed sites. Fields, roadsides, empty lots.




July to October


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 22, 28, 29, 30.









  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Asterales (sunflowers, bellflowers, fanflowers, and allies)  


Asteraceae (sunflowers, daisies, asters, and allies)  
  Subfamily Asteroideae  
  Supertribe Asterodae  
  Tribe Astereae (asters and allies)  
  Subtribe Conyzinae  
  Genus Erigeron (fleabanes and horseweeds)  

This species was originally named Erigeron canadensis in 1753. It was transferred to the genus Conyza by Cronquist in 1943. It was later determined that Conyza as traditionally circumscribed is nested within Erigeron and is polyphyletic or paraphyletic. The species was subsequently transferred back to the genus Erigeron. Both names, Erigeron canadensis and Conyza canadensis, are in widespread use today.


Subordinate Taxa






Conyza canadensis

Leptilon canadense


Common Names



Canada horseweed

Canadian fleabane

Canadian hogweed

Canadian horseweed



horseweed fleabane

mares tail



















Long and narrow with parallel sides, as in a blade of grass.

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    Canadian horseweed   Canadian horseweed  


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    Canadian horseweed      


    Canadian horseweed   Canadian horseweed  
    Canadian horseweed      


    Canadian horseweed   Canadian horseweed  
    Canadian horseweed      






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Other Videos
  How To Identify Horseweed Erigeron canadensis identification

Published on Sep 25, 2013

How to identify horseweed, Erigeron canadensis identification. Horseweed belongs in the aster family, has medicinal properties and is reportedly a real good choice for a spindle used in friction fire with the hand drill.

To see mushroom, plant, garden and outdoor photos, field guides I use, identification books, and other interesting stuff visit me on Facebook

Thanks for watching, commenting, subscribing to, and supporting this channel. If you like this video please give a thumbs up and share it with others. If you have any questions or tips please leave a comment.

  Canadian Horseweed (Erigeron canadensis) - 2012-08-21

Published on Aug 30, 2012

Erigeron canadensis (formerly Erigeron canadensis L.) is an annual plant native throughout most of North America and Central America. Common names include Horseweed, Canadian Horseweed, Canadian Fleabane, Coltstail, Marestail and Butterweed.

De Canadese fijnstraal (Erigeron canadensis, synoniem: Erigeron canadensis) is een tot 1 m hoge, maar op voedselrijke grond tot 1,5 m hoge, eenjarige plant uit de composietenfamilie (Asteraceae).

  Eat The Weeds: Episode 130: Horseweed

Uploaded on Aug 24, 2011

Spice, food and source of a drill for making fire by hand, Horseweed is found around the world.




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Location: Memramcook, NB, Canada

Canadian horseweed  

Afton State Park

Agassiz Dunes SNA (MN DNR)

Avon Hills Forest SNA, North Unit

Badoura Jack Pine Woodland SNA

Bertram Chain of Lakes Regional Park

Big Stone Lake State Park

Blaine Preserve SNA

Blazing Star Prairie

Blazing Star Prairie Addition Preserve, South Unit

Blue Mounds State Park

Buffalo River State Park

Bur Oak WMA

Butternut Valley Prairie SNA

Carpenter St. Croix Valley Nature Center

Carver Highlands WMA, South Unit

Cedar Mountain SNA

Cedar Rock SNA

Charles A. Lindbergh State Park

Chippewa Prairie

Clear Lake SNA

Clifton E. French Regional Park

Cottonwood River Prairie SNA

Crosby Farm Regional Park

Crow Wing State Park

Crow-Hassan Park Reserve

Des Moines River SNA

Dodge Nature Center

Elm Creek Park Reserve

Felton Prairie SNA, Bicentennial Unit

Flandrau State Park

Foxhome Prairie

Frontenac State Park

Glacial Lakes State Park

Glendalough State Park

Grey Cloud Dunes SNA

Hyland Lake Park Reserve

Iron Horse Prairie SNA

John Murtaugh Memorial WMA

Joseph A. Tauer Prairie SNA

Kellogg Weaver Dunes SNA, Kellogg Weaver Unit

Kilen Woods State Park

Lake Bronson State Park

Lake Carlos State Park

Lake Louise State Park

Lake Rebecca Park Reserve

Lebanon Hills Regional Park

Leif Mountain

Lester Lake SNA

Lost Valley Prairie SNA

Maplewood State Park

Margherita Preserve-Audubon Prairie

McKnight Prairie

Mille Lacs Kathio State Park

Minneopa State Park

Minnesota Valley NWR, Chaska Unit

Minnesota Valley NWR, Louisville Swamp Unit

Minnesota Valley NWR, Rapids Lake Unit

Minnesota Valley NWR, Wilkie Unit

Minnesota Valley State Recreation Area, Lawrence Unit

Mississippi River County Park

Monson Lake State Park

Mound Prairie SNA

Mound Spring Prairie SNA, North Unit

Northern Tallgrass Prairie NWR, Hoffman Unit

Old Mill State Park

Ordway Prairie

Osmundson Prairie SNA

Pankratz Memorial Prairie, North Unit

Pembina Trail Preserve SNA, Crookston Prairie Unit

Pin Oak Prairie SNA

Pine Bend Bluffs SNA

Plover Prairie, East Unit

Prairie Coteau SNA

Prairie Creek WMA, Koester Prairie Unit

Prairie Smoke Dunes SNA

Racine Prairie SNA

Red Rock Prairie

Rice Lake Savanna SNA

River Terrace Prairie SNA

Rock Ridge Prairie SNA

Roscoe Prairie SNA

St. Croix Savanna SNA

Sand Prairie Wildlife Management and Environmental Education Area

Sandpiper Prairie SNA

Savage Fen SNA

Schaefer Prairie

Seminary Fen SNA

Seven Sisters Prairie

Sibley State Park

Split Rock Creek State Park

Spring Creek Prairie SNA

Spring Prairie Preserve

Springbrook Nature Center

Staffanson Prairie

Swedes Forest SNA

Tamarack Nature Center

Town Hall Prairie

Twin Valley Prairie Addition

Twin Valley WMA: North Unit

Uncas Dunes SNA

Valley View Park

Vermillion River WMA

Whitetail Woods Regional Park

Whitewater State Park

Wild River State Park

William O’Brien State Park

Woodbury WMA

Yellow Bank Hills SNA







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