trefle.io · Taken Sep 19, 2021 by Jochen Schäfer (cc-by-sa)
Asteraceae
Horseweed
Ambrosia trifida
Also known as Canadian fleabane, Colt's tail, Marestail, Ambrosia trifida var. aptera
Native Plants · Ragweed · Weed · Allergenic · Annual · Invasive Weed · Disturbed Soil · Wind Pollinated · Native North America · Tall Growing · Wildflower
Giant ragweed (horseweed) is a vigorous, fast-growing annual weed that establishes readily in disturbed soils and full sun conditions. It is rarely intentionally cultivated and requires active management to prevent it from spreading and overwhelming garden beds. Be aware that its abundant wind-dispersed pollen is a major cause of seasonal allergies.
Growing conditions
The details behind the basics
- Daily light
- 8 hours
- Watering
- Water moderately; tolerates average moisture and occasional dry periods · Every 7-10 days
- Maintenance
- High
- Soil
- loam
- Soil pH
- 7.5–8
- Temperature
- -20°F to 90°F
- Cycle
- Perennial
- Propagation
- Seed, Division
Hardiness
USDA 3a-10b
Form & growth
Mature size and habit
- Mature height
- 12 in – 6 ft
- Spread
- 3 ft
- Spacing
- 24 in apart
- Growth rate
- Moderate
- Root depth
- Medium
- Flowers
- No
- Foliage
- Medium
Ecology & origin
Where it belongs and what it brings
- Native to
- Alabama, Alberta, Arizona, Arkansas, Austria, Baltic States, Belarus, Belgium, Bulgaria, California, Central European Rus, China North-Central, China South-Central, China Southeast, Colorado, Connecticut, Czechoslovakia, Delaware, Denmark, District Of Columbia
- Attracts
- Birds
Sources: trefle, usda
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