Canadian horseweed
Conyza canadensis · Asteraceae
Canadian horseweed (Conyza canadensis) is a biennial herbaceous plant in the Asteraceae family. It is native to North America. USDA records it as hardy in zone 12 and warmer, down to about 52°F.
At a glance
| Type | forb-herb USDA |
|---|---|
| Lifecycle | biennial USDA |
| Native status | native USDA |
| Mature height | 5 ft USDA |
| Light | full-sun USDA |
| Water need | medium USDA |
| Growth rate | rapid USDA |
| Soil pH | 4.8–7.2 USDA |
| Flower color | White USDA |
| Hardiness zones | 12 and warmer USDA |
| Guild layer | understory Derived |
| Nursery availability | No Known Source USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It needs full sun. USDA rates it as having moderate water needs. It is recorded on soils from pH 4.8 to 7.2 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 12; USDA publishes no warm-end limit, so gardeners in warmer zones should check local heat tolerance separately.
Size and growth
At maturity it reaches about 5 ft, making it a low to knee-height plant. It grows quickly, which matters when you are timing a planting around the layers above it.
Role in a guild
Understory. In a layered planting this is the layer beneath the canopy, tall enough to hold structure but shaded from above. We derive the layer from the plant's growth habit and mature height using a fixed rule, so the same inputs always produce the same layer.
Tags
Related plants
Similar role and hardiness
- wili wili Erythrina sandwicensis
- common sunflower Helianthus annuus
- foxtail millet Setaria italica
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol COCA5, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
commercial_availability— quoted from USDA PLANTSduration— quoted from USDA PLANTSflower_color— quoted from USDA PLANTSgrowth_habit— quoted from USDA PLANTSgrowth_rate— quoted from USDA PLANTSguild_role— derived by rule from USDA columnsmature_height_ft— quoted from USDA PLANTSmoisture— quoted from USDA PLANTSnative_status— quoted from USDA PLANTSnitrogen_fixer— quoted from USDA PLANTSpet_safe— quoted from USDA PLANTSph_max— quoted from USDA PLANTSph_min— quoted from USDA PLANTSshade_tolerance— quoted from USDA PLANTStemperature_min_f— quoted from USDA PLANTSzone_min— quoted from USDA PLANTS
Read our full data sources and methodology.
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