Quick answer: Swamp milkweed (Asclepias incarnata) is native to 25 states. What's commonly sold under this name is the true wild species. It's typically seeds, verified 16 Sep 2026.
Where it's native
Listed in the register as native to these states. Click a state for its full native-plant guide.
Growing conditions
From the Lady Bird Johnson Wildflower Center Native Plant Database.
| Sun | Sun, Part Shade |
|---|---|
| Water | High water |
| Soil | Rich, wet, muddy to average garden moisture, tolerates mucky clay |
| Bloom | Jun-Oct |
| Height | Up to 5 ft |
| Wildlife value | Larval host for Monarch and Queen; attracts hummingbirds and bees |
All parts toxic only in large quantities; symptoms vomiting, stupor, weakness, spasms. Toxic principle: cardiac glycosides and resinoids.
Buying it
Sold true to the wild species as of the last check (16 Sep 2026), via Amazon.
Sold as: Seeds via Amazon · listing verified 16 Sep 2026
See where to buy →Also listed under
Get the full buying guide
Every pick worth knowing across pollinators, shade, drought and more, in one PDF, with the tradeoffs spelled out. No spam, unsubscribe anytime.