Skip Navigation

Species Search:
FieldGuidesthreatened and/or endangered search resultsthreatened and/or endangered

previous  | next

Horseweed Conyza canadensis (Erigeron canadensis)


enlarge +

credit: H. Zell/CCSA

All Images


Get Our Newsletters


Advanced Search

Alternate name: Canadian Horseweed

Family: Asteraceae, Aster view all from this family

Description Native herbaceous annual or short-lived perennial.
Habit: slender, erect, weedy, coarse; leafy stem, usually unbranched and hairy; taprooted.
Height: 1.6-6.5 ft (0.5-2 m) or more.
Leaf: alternate, ascending or arching, narrow, pointed; 3/4-4 in (20-100 cm) long, 1/8-1/2 in (2-10 mm) wide.
Flower: small flowerhead on a cylindrical bract, 3/16 in (5 mm) wide, with tiny rays, white or pale purple, around a yellow to pink disk; held in a dense terminal cluster.
Fruit: miniscule dry shell in a fluffy sphere.

Flower April to November.

Habitat Fields, meadows, and gardens; shorelines, riparian and moist disturbed areas; to 6500 ft (2000 m).

Range Found throughout North America; also in Hawaii.

Discussion Also known as: Canadian horseweed, horseweed fleabane, fleabane, mares tail. This plant is considered weedy or invasive in many areas. Believed to be native to eastern North America, it is now naturalized around the world.