Light Needs
Mature Height
Mature Spread
Growing Zones
Sullivant’s Milkweed (Asclepias sullivantii), also known as Prairie Milkweed, is a show-stopping native perennial with clusters of soft pink flowers perched atop sturdy, unbranched stems. Reaching heights of 3 to 4 feet, this milkweed features smooth, succulent-like leaves with reddish midveins, creating a striking contrast against its rosy blooms. Blooming from early summer through August, it’s a magnet for monarch butterflies, hummingbirds, and beneficial pollinators. Its refined appearance and less aggressive nature make it an excellent alternative to common milkweed for gardeners seeking structure and elegance.
Native to the central United States, Sullivant’s Milkweed thrives in sunny prairies, meadows, and rain gardens. This species tolerates clay and loamy soils with moderate moisture, making it ideal for low-lying areas or borders with consistent watering. Its fragrant blooms add an inviting scent to naturalized plantings and pollinator habitats. As a larval host for monarch and queen butterflies, as well as a nectar source for hummingbirds and bees, Sullivant’s Milkweed supports biodiversity while remaining resistant to deer browsing.
Sullivant’s Milkweed Care
Plant Sullivant’s Milkweed in full sun to promote flowering and strong growth. It prefers medium-moisture, well-drained soil but can tolerate wetter conditions, making it suitable for rain gardens or streamside plantings. Water regularly during the first growing season to help establish its deep taproot, which provides drought resilience in subsequent years. Fertilization is generally unnecessary, though adding compost at planting can enrich the soil and promote early vigor.
To encourage fresh growth and prevent self-seeding, deadhead spent blooms throughout the summer. In late fall or early spring, trim stems back to just above the soil line to support healthy regrowth. Avoid disturbing the plant’s deep rhizomes during pruning or transplanting, as they help anchor the plant in moist soils and contribute to its longevity.
Sullivant’s Milkweed Spacing
Space plants around 24 inches apart to allow for their spreading habit via rhizomes. In mass plantings or prairie gardens, closer spacing creates a dense, cohesive look, while wider spacing highlights the plant’s upright, architectural form. For container growth, choose a pot at least 14 inches wide and deep to accommodate its robust root system.
Image(s) Courtesy of - https://www.flickr.com/photos/gmayfield10/3241297771/
Sullivants Milkweed Plant Facts
Growing Conditions
- Hardiness ZonesGrowing Zones
- USDA Zones 3 to 7 (perennial); grown as an annual elsewhere (outdoors year-round); grown indoors elsewhere (outdoors year-round); grown in containers elsewhere (grown as a seasonal crop)
- Sun Exposure
- Full Sun (6+ Hours Direct Sun)
- Mature Height
- 2-3 Feet
- Mature Spread
- 1 Foot
- Growth Rate
- Moderate
- Growth Habit
- , Clumping, Upright
- Water Needs
- Consistently Moist
Flowers & Foliage
- Flower Colors
- , Pink, Purple, White
- Flower Description
- Pinkish-White To Pinkish-Purple, Star-Like Flowers
- Bloom Time
- Early to Mid-Summer
- Foliage Color
- , Green
- Foliage Description
- Medium to dark green with pinkish-red midribs
- Foliage Type
- , Herbaceous
- Seasonal Interest
- , Summer Flowering
Garden Benefits
Plant Overview
- Common Name
- Sullivants Milkweed
- Also Known As
- smooth milkweed, Sullivant's milkweed or prairie milkweed
- Botanical Name
- Asclepias sullivantii
- Brand
- Proven Selections
Simple Plant Spacing Calculator
Please Note: The pictures below are to give a general representation of the different container sizes. The actual size/ages of plants are estimates and will vary based on type of plant, time of year, last pruning & many other factors.
Also Known As:
Quart
Plant Age:
~ 6 months - 1 year
Plant Size:
~ 4"-8"
Pot Size:
~ 4.75"H x 4.5"W
Volume:
1.50 quarts
Also Known As:
2.5 Quart Pot
Plant Age:
~ 1 - 2 years old
Plant Size:
~ 8"-12"
Pot Size:
~ 6.5"H x 6.5"W
Volume:
2.20-2.30 quarts
Also Known As:
#1 Container
1 Gallon
Plant Age:
~ 1 - 2 years old
Plant Size:
~ 10"-14"
Pot Size:
~ 7"H x 7.75"W
Volume:
2.26-3.73 quarts
Also Known As:
#2 Container
2 Gallon
Plant Age:
~ 1.5 - 3 years old
Plant Size:
~ 12"-18"
Pot Size:
~ 9.5"H x 9.5"W
Volume:
1.19-1.76 gallons
Also Known As:
#3 Container
3 Gallon
Plant Age:
~ 2 - 4 years old
Plant Size:
~ 12"-30"
Pot Size:
~9.5"H x 11"W
Volume:
2.32-2.76 gallons
Also Known As:
#5 Container
5 Gallon
Plant Age:
~3-4 years old
Plant Size:
~ 20" - 60"
Pot Size:
~11" H x 10 1/2” W
Volume:
3.5 - 4 gallons
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