Common milkweed vs Swamp milkweed
Both are native host plants for monarch caterpillars, with pink flowers in midsummer. Common milkweed has broad leaves and drooping balls of dusky pink, heavily scented flowers, and it runs far underground and comes up several feet away: a plant for a meadow or a wild corner. Swamp milkweed stays in a clump, has rose-pink, vanilla-scented flowers on willowy stems, and despite its name grows in ordinary garden soil: the one for a border.
 Common milkweedAsclepias syriaca |  Swamp milkweedAsclepias incarnata | |
|---|---|---|
| Size | 4 ft tall, 24 in wide | 4 ft tall, 24 in wide |
| Plant | 18 in apart | 24 in apart |
| Zones | 3 to 9 | 3 to 9 |
| Light | Full sun | Full sun to part sun |
| Soil | Well-drained, average fertility | Evenly moist, average fertility |
| Flowers | Late June to early August; pink | Early July to early August; pink, white |
| Leaves | Bold, herbaceous | Medium, herbaceous |
| Job in a bed | Drift | Drift |
| Pets | Toxic (moderate) | Toxic (moderate) |
| Deer | Resistant | Resistant |
| Native | Yes | Yes |
| Spread | High risk | Low risk |
Rows where they differ are marked. Flowering times are for zone 5.
Which to choose
- Choose common milkweed for dry summers and more wildlife.
- Choose swamp milkweed for more shade and moist soil.
Can they grow together?
Yes: they grow in the same conditions. What swamp milkweed brings beside common milkweed: in flower together for five weeks, from early July; medium leaves against its bold ones. They share full sun and zones 3 to 9.
Read more: all about common milkweed, and all about swamp milkweed, each with a bed the planner designed around it.