Tropical Milkweed
Asclepias curassavica — Dogbane Family
A native perennial wildflower in the Dogbane Family that blooms in summer.
Planting Guide
When to plant
Plant in spring after the last frost date or in early fall, 6 weeks before the first frost. Container plants establish faster than bare root.
Spacing
Space plants 1.5–2.0 feet apart. Closer spacing fills in faster and suppresses weeds; wider spacing gives each plant room to reach full size.
Root system
Roots reach at least 12 inches deep at maturity. Plant the crown at or just below soil level.
Growing Conditions
Sunlight
Full sun — 6 or more hours of direct sunlight per day. This species does not tolerate shade and will thin out or fail to bloom in shadier spots.
Soil & pH
Prefers a wide pH range from acidic to neutral (pH 6.0–7.5). Most average garden soils fall in this range; a quick soil test confirms your starting point.
Watering
Moderate water needs. Water deeply once or twice per week during the first season. Established plants handle brief dry spells but benefit from occasional watering during prolonged dry periods. Once established (typically 1–2 seasons), it shows moderate drought tolerance and can go extended periods without supplemental water.
Seasonal Care
- Cut back dead stems from last year to 2–3 inches above ground as new growth emerges.
- Top-dress with a thin layer of compost to support the season's growth.
- Deadhead spent flowers regularly to extend bloom period and prevent excessive self-seeding.
- Water during extended dry periods (10+ days without rain), especially in the first season.
- No major pruning needed; remove any diseased or damaged foliage promptly.
- Leave stems and seed heads standing through fall and winter to support overwintering insects and birds.
- Divide or transplant in early fall (6 weeks before first frost) for best establishment.
- Leave the plant standing — hollow stems shelter native bees and other beneficial insects overwinter.
- The seed heads attract finches and sparrows through the coldest months.
- No mulching is needed for established plants; a thin layer of leaves is fine around the crown.
Wildlife & Garden Value
Ecological benefits
- Supports a range of native pollinators including native bees, butterflies, and beneficial predatory insects throughout the growing season.
Landscaping uses
- Mixed perennial border or cottage garden planting.
- Native meadow or pollinator garden seed mix component.
Where to Buy Tropical Milkweed
Buy from specialist native plant nurseries to get the true species rather than a cultivar with reduced wildlife value.
- American Meadows — native seeds and plants
- Prairie Moon Nursery — specialist native plant nursery
- Burpee — seeds with planting instructions