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Index / Search / Conyza canadensis

§1 Plant

Conyza canadensis (L.) Cronquist

vernacular Canadian horseweed — species · Asteraceae

USDA
COCA5
GBIF
3146791 syn.
Rank
species
Canadian horseweed (Conyza canadensis)
Platephotograph · Scott MorrisCC BY source · iNaturalist ↗

§2Habit & range

Habit and range

Growth habit
Forb/herb
Duration
Annual, Biennial
Group
Dicot
Family
Asteraceae Bercht. & J. Presl
Genus
Conyza
§2a

Native status, by region

  • AK Alaska Introduced
  • CAN Canada Native
  • HI Hawaii Introduced
  • L48 Lower 48 States Native
  • NAV Navassa Island Native
  • PB Pacific Basin (except Hawaii) Introduced
  • PR Puerto Rico Native
  • SPM St. Pierre & Miquelon Native
  • VI U.S. Virgin Islands Native
§2b

County-level range

· 1,343 counties across 31 states/territories
Legend Native · 1341 Introduced · 2 Both · 0 Hover a county for detail.

§3Cultivation specs · USDA

Recorded by the USDA Plant Materials Program.

§3a

Tolerances

Drought
Low
Shade
High
Moisture use
Medium
Fire
Low
Salinity
None
Anaerobic
Low
CaCO₃
Low
Hedging
None
§3b

Climate & soil

Cold tolerance
52 °F minimum
Frost-free days
60 min.
Precipitation
14–55 in/yr
pH range
4.8–7.2
Root depth
6 in min.
Fertility need
Medium
Soil texture
coarse, medium, fine
§3c

Form & growth

Growth form
Single Crown
Growth rate
Rapid
Mature height
5 ft
Foliage texture
Coarse
Foliage colour
Green
Porosity (summer)
Porous
Porosity (winter)
Porous
Flower colour
White
Fruit colour
Brown
Fire resistant
No
N fixation
None
Toxicity
None
§3d

Reproduction

Bloom period
Indeterminate
Seed abundance
High
Spread rate
Rapid
Stratify
No
Seeds / lb
700,000
Propagation
seed
§3e

Use & availability

Commercial availability
No Known Source
Nursery stock
No
Palatable, human
No
Lumber
No
Christmas tree
No

§4Counties, by state

Recorded in 1,343 counties across 31 states/territories.

Alabama view state ↗ 11 N ▾
Alaska view state ↗ 2 I ▾
Arizona view state ↗ 15 N ▾
Arkansas view state ↗ 61 N ▾
Delaware view state ↗ 3 N ▾
District of Columbia view state ↗ 1 N ▾
Florida view state ↗ 62 N ▾
Georgia view state ↗ 38 N ▾
Illinois view state ↗ 102 N ▾
Indiana view state ↗ 68 N ▾
Iowa view state ↗ 22 N ▾
Kansas view state ↗ 105 N ▾
Kentucky view state ↗ 55 N ▾
Louisiana view state ↗ 61 N ▾
Maine view state ↗ 15 N ▾
Massachusetts view state ↗ 14 N ▾
Michigan view state ↗ 70 N ▾
Minnesota view state ↗ 67 N ▾
Mississippi view state ↗ 81 N ▾
Montana view state ↗ 30 N ▾
New Hampshire view state ↗ 9 N ▾
New Jersey view state ↗ 19 N ▾
New York view state ↗ 35 N ▾
North Carolina view state ↗ 97 N ▾
Pennsylvania view state ↗ 66 N ▾
Rhode Island view state ↗ 5 N ▾
South Carolina view state ↗ 42 N ▾
Tennessee view state ↗ 43 N ▾
Vermont view state ↗ 10 N ▾
Virginia view state ↗ 96 N ▾
West Virginia view state ↗ 38 N ▾

§5Sources & provenance

USDA PLANTS

Symbol, taxonomy, distribution, cultivation specs, native status. Public domain.

plants.usda.gov/COCA5 ↗

GBIF Backbone

Canonical taxonomic identity, synonym resolution, cross-refs. CC0.

gbif.org/species/3146791 ↗

Record version

Cached and built locally. Source version on this record:

usda-plants-mt-2026-05-26

fetched 2026-05-26T07:25:30Z