Swamp Milkweed Seeds – Asclepias incarnata

Create a summer gathering place for butterflies with swamp milkweed (Asclepias incarnata). Also known as rose milkweed or marsh milkweed, this United States native perennial carries rounded clusters of fragrant pink flowers with pale pink to white accents above upright stems and narrow green leaves.

Plant it in a sunny, moisture-rich border and enjoy the activity as butterflies visit its nectar-filled blooms. Swamp milkweed also serves as a host plant for monarch caterpillars, making it a purposeful addition to a butterfly garden.

Plant Highlights

• Botanical name: Asclepias incarnata.
• Common names: Swamp milkweed, rose milkweed and marsh milkweed.
• Life cycle: Perennial.
• Flowers: Fragrant pink clusters with lighter pink to white details.
• Bloom season: Summer, typically June–August depending on climate.
• Mature height: Approximately 36–60 inches.
• Plant spacing: 18–24 inches.
• Light: Full sun.
• Soil moisture: Moist to wet; avoid allowing the planting area to dry out.
• USDA hardiness zones: 3a–9.

Choose Your Seed Size

Available in 100-seed, 500-seed, 1/4 oz and 1 oz options. Weight-based packages are sold by weight, not by a guaranteed number of plants. This listing is for seeds, not live plants.

Sowing Instructions

Fall sowing: Sow just below the soil surface in late fall so seeds experience natural winter conditions before spring growth. Thin emerging seedlings to allow the strongest plants adequate room.

Spring sowing: Mix seeds with moist sand and refrigerate for 30 days before direct sowing. Keep the sowing area moist while seedlings establish. Handle young plants gently and minimize root disturbance when transplanting.

Growing & Care

Choose full sun and a location with reliable soil moisture. Swamp milkweed is well suited to moist borders and butterfly gardens, and can also grow in average garden soil when moisture is maintained. Mulch to help retain moisture, water during dry periods and reduce competition from weeds.

Cut Flowers

For fresh arrangements, select clusters with recently opened flowers and cut stems to the length needed. Wear gloves and take care around the milky sap.

Handling Precautions

Ornamental plant, not for consumption. The milky sap may irritate skin. Avoid contact with eyes, wash hands and tools after handling, and keep plant material away from children and pets.