Swamp Milkweed plant profile
Asclepias incarnata
A perennial flower for full sun.
Last updated .
When to plant
When to plant Swamp Milkweed
Plant in full sun to partial shade in moist soils. It is native to wet sites but adapts to drier moist clay or loam, and it grows well from seed sown in spring.
The calendar shows this cited seasonal window as an approximate band. It does not convert the season into frost-adjusted dates.
Open Swamp Milkweed in my garden calendarShows the source-backed planting season, not frost-adjusted dates.
Growing conditions
- Sun
- Full sun
- Soil pH
- 6 to 8
- Lifecycle
- Perennial
- Hardiness
- Zones 3 to 9Find my hardiness zone
Next steps
Continue with Swamp Milkweed
Evidence trail
Evidence behind this profile
Original extension and institutional publications behind the planting, care, and safety facts on this page.
- Asclepias incarnata (Marsh Milkweed, Swamp Butterfly Weed, Swamp Milkweed)
NC State Extension Gardener Plant Toolbox. Supports general reference. Checked 2026-06-18.
- Toxic and Non-Toxic Plants: Milkweed (Asclepias species) entry
ASPCA Animal Poison Control Center. Supports pet-safety verdicts for dogs and cats. Checked 2026-07-18.