Antelope Horn Milkweed
Asclepias asperula
Last reviewed: June 2026
Asclepias asperula (Antelope Horn Milkweed) is a native forb found across the southwestern and Great Plains states, blooming from March through November. This drought-tolerant wildflower attracts butterflies and bees with its distinctive white flower clusters.
Antelope Horn Milkweed is toxic to dogs and cats.
Listed as toxic by the ASPCA Animal Poison Control Center (opens in new tab) (last reviewed 2026-05-21). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435and your veterinarian's emergency line.
Pollinator Patch flags toxic plants so you can choose a pet-safe native alternative for your yard.
Light
full sun
Water
medium
Size
12"–24" H × 12"–24" W
Bloom
Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov
Native to
AZ, CA, CO, ID and 7 more states
Pollinators
butterflies, bees
Browse plants for this ecoregion
Antelope Horn Milkweed is a compact native perennial with distinctive greenish-white flower clusters and narrow, grayish-green leaves. It blooms reliably from spring through fall and goes dormant in winter, disappearing completely underground. This drought-tolerant plant works well in xeriscaped gardens and native plant borders.
Growing Antelope Horn Milkweed
Grow Antelope Horn Milkweed in full sun and medium water. Mature plants reach 12 to 24 inches tall and spread 12 to 24 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Antelope Horn Milkweed is an HOA-friendly choice. Maintenance level: low. Tidiness: 2 out of 5.
Works well in: front yard, foundation, street edge, mid zone.
Wildlife value
Essential host plant for monarch butterfly caterpillars and attracts numerous other butterflies and native bees with its nectar-rich flowers. The long blooming season provides consistent pollinator support throughout the growing season.
Common questions
- When does Antelope Horn Milkweed bloom?
- Asclepias asperula has an exceptionally long blooming period, producing flowers from March through November in favorable conditions.
- Where is Antelope Horn Milkweed native?
- This species is native to Arizona, California, Colorado, Idaho, Kansas, Nebraska, New Mexico, Nevada, Oklahoma, Texas, and Utah, primarily in arid and semi-arid regions.
- What pollinators visit Antelope Horn Milkweed?
- Asclepias asperula attracts various butterflies and native bees, making it valuable for pollinator gardens in dry regions.
- Is Antelope Horn Milkweed toxic to dogs?
- Yes. Antelope Horn Milkweed is listed as toxic to dogs by the ASPCA Animal Poison Control Center (aspca.org). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Antelope Horn Milkweed toxic to cats?
- Yes. Antelope Horn Milkweed is listed as toxic to cats by the ASPCA Animal Poison Control Center (aspca.org). If your cat has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Antelope Horn Milkweed HOA-friendly?
- Antelope Horn Milkweed is generally an HOA-friendly choice in the right placement, with low maintenance.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Pollinator Patch flags toxic plants like Antelope Horn Milkweed and shows pet-safe natives for your ecoregion instead.