Zone 4 · Swamp Milkweed
Planting Swamp Milkweed in Zone 4
Asclepias incarnata
✅ Swamp Milkweed thrives in zone 4 (hardy 3–9)
Can I plant today?
✅ Safe to plant Swamp Milkweed outside
Last frost has passed. Plant in spring in moist soil. Monarch host plant; more garden-polite than common milkweed.
Evaluated for June 13, 2026 ·
Zone's last frost
around May 15
Zone's first frost
around September 15
Bloom window
July – August
Peak bloom
July
Sun required
full sun
Mature height
48"
Spacing
24" apart
Type
perennial
How to plant Swamp Milkweed in zone 4
Plant in spring in moist soil. Monarch host plant; more garden-polite than common milkweed.
Pair with these for continuous bloom
Swamp Milkweed peaks in July. These companions keep your bed in color before and after.
Want a full bed designed for zone 4?
Sign up free. GimmeBlooms builds a bloom-succession layout withSwamp Milkweed and 3–5 perfect companions.
Design my bed →