Plant DetailShow Menu

Canadian Horseweed Erigeron canadensis

Previously known as:

  • Conyza canadensis
Phonetic Spelling
er-IJ-er-on ka-na-DEN-sis
This plant has low severity poison characteristics.
See below
Description

Horseweed is a winter annual in the aster family (Asteraceae). Peak germination is in late autumn and early spring but sporadic germination may occur anytime except summer. It forms a rosette of hairy leaves. In spring, plants bolt upright 3 to 6 feet tall. Plants have a tap root with some fibrous roots making them difficult to remove.  Individual flowers are small, with white ray flowers and yellow disk flowers.  Do not let plants go to seed in the nursery. Control horseweed around the property to prevent spread. When hand weeding, remove completely as plants can re-sprout from broken stems. Horseweed can be managed by preemergence broadleaf herbicides.

Note: glyphosate-resistant horseweed has been reported in areas where glyphosate-resistant crops are grown.

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#annual#white flowers#weed#weedy#winter annual weed#high maintenance#daisy-like#arable land#wind dispersed seeds#hairy leaves#annual weed#cool season weed
 
Cultivars / Varieties:
Tags:
#annual#white flowers#weed#weedy#winter annual weed#high maintenance#daisy-like#arable land#wind dispersed seeds#hairy leaves#annual weed#cool season weed
  • Attributes:
    Genus:
    Erigeron
    Species:
    canadensis
    Family:
    Asteraceae
    Life Cycle:
    Annual
    Country Or Region Of Origin:
    New World
    Distribution:
    wind
    Dimensions:
    Height: 0 ft. 6 in. - 7 ft. 0 in.
    Width: 0 ft. 6 in. - 2 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Annual
    Weed
    Woody Plant Leaf Characteristics:
    Deciduous
    Growth Rate:
    Medium
    Maintenance:
    High
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil pH:
    Acid (<6.0)
    Alkaline (>8.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Available Space To Plant:
    Less than 12 inches
    12 inches-3 feet
    3 feet-6 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
  • Fruit:
    Fruit Color:
    Gold/Yellow
    Gray/Silver
    Fruit Type:
    Achene
    Fruit Length:
    < 1 inch
    Fruit Description:
    Yellow to gray elliptical achenes with fluffy white hairs that aid in wind dispersal.
  • Flowers:
    Flower Color:
    Cream/Tan
    White
    Flower Inflorescence:
    Panicle
    Flower Bloom Time:
    Fall
    Summer
    Flower Shape:
    Urn
    Flower Petals:
    7 - 20 petals/rays
    Flower Size:
    < 1 inch
    Flower Description:
    Self-fertile Pea sized white flowers in a terminal panicle 1 1/2' long and 1/2' wide. Additoinal flowers form in the axils of leaves. Individual flowers are 2-3 mm in size and are urn to cylindrical in shape. Flowers appear for a three week period any time between mid-summer through fall.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Feel:
    Smooth
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Rosulate
    Leaf Shape:
    Elliptical
    Lanceolate
    Leaf Margin:
    Dentate
    Entire
    Hairs Present:
    Yes
    Leaf Length:
    1-3 inches
    Leaf Width:
    < 1 inch
    Leaf Description:
    Leaves form as a basal rosette throughout fall and winter until late spring when plants bolt upright; leaves will become progressively smaller upwards on the stem but average 2"-3 1/2" long and 1/2" wide. They occasionally have teeth along the margin otherwise are entire.
  • Stem:
    Stem Color:
    Brown/Copper
    Green
    Red/Burgundy
    Stem Is Aromatic:
    No
    Stem Surface:
    Hairy (pubescent)
    Stem Description:
    Unbranched except at the top where flowers appear, light green, angular with white hairs.
  • Landscape:
    Landscape Location:
    Lawn
    Problems:
    Weedy
  • Poisonous to Humans:
    Poison Severity:
    Low
    Poison Symptoms:
    Mucosal irritation to humans and livestock
    Poison Toxic Principle:
    Tannic acid, gallic acid, volatile oils
    Causes Contact Dermatitis:
    No
    Poison Part:
    Leaves