Canadian Horseweed Erigeron canadensis
Other Common Name(s):
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
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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:
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- Tags:
- Cultivars / Varieties:
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- Tags:
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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.
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Whole Plant Traits:
- Plant Type:
- Annual
- Weed
- Woody Plant Leaf Characteristics:
- Deciduous
- Growth Rate:
- Medium
- Maintenance:
- High
- Texture:
- Medium
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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
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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.
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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.
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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.
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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.
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Landscape:
- Landscape Location:
- Lawn
- Problems:
- Weedy
