Clump-forming milkweed with deep pink flower umbels, suited to wet soils and pond edges. Better behaved in gardens than common milkweed.
Hardiness ratings
| System | Rating | Temperature range | How to read it |
|---|---|---|---|
| USDA hardiness zone | Zone 3–8 | −40 °C to −6.7 °C | Plant tolerates down to this zone |
| RHS hardiness rating | H7 | down to −20 °C | Plant needs at least this level of cold tolerance |
| Canadian plant hardiness zone | Zone 3–8 | −34 °C to −1 °C | Plant tolerates down to this zone |
| Australian (ANBG) zone | Zone 1–5 | −15 °C to 10 °C | Plant tolerates down to this zone |
Growing notes
- Larval food plant for the monarch butterfly — preferred in wet sites where common milkweed will not thrive
- Tolerates boggy, seasonally flooded soil
- Forms tidy clumps rather than running aggressively — easier to place in mixed borders
Pet caution: Swamp milkweed is listed as potentially harmful to cats and/or dogs. Keep pets from grazing on it, and contact a vet if you suspect your animal has eaten some.
Categories
Related plants
Cross-check Swamp milkweed against your zones