Wildflower (forb) · Asclepiadaceae
Showy milkweed
Asclepias speciosa
Showy milkweed is recorded as native to 19 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 475 counties of those states by USDA PLANTS.
Key facts · USDA PLANTS
Showy milkweed at a glance
- Native in
- 475 counties, across 19 states and territories
- Estimated cold hardiness
- Zone 4a PLANTS minimum temperature −33°F
- Mature height
- 6 ft PLANTS mature height
- Light and water
- Full sun (shade-intolerant) Medium water use
Estimated cold hardiness: zone 4a. PLANTS gives a minimum temperature of −33°F; zone 4a winters bottom out at −30°F, the coldest half-zone that stays within that limit.
Showy milkweed is recorded as native to 19 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 475 counties of those states by USDA PLANTS.
Counties where it is native
The 15 counties with the most ZIP codes among the 475 where it is listed.
Native counties by state
- Arizona 4 counties
- California 28 counties
- Colorado 38 counties
- Idaho 28 counties
- Iowa 4 counties
- Kansas 55 counties
- Minnesota 49 counties
- Montana 30 counties
- Nebraska 35 counties
- Nevada 16 counties
- New Mexico 16 counties
- North Dakota 36 counties
- Oklahoma 11 counties
- Oregon 26 counties
- South Dakota 26 counties
- Texas 7 counties
- Utah 29 counties
- Washington 18 counties
- Wyoming 19 counties
Growing traits
Values from the PLANTS characteristics record. “Not recorded” means PLANTS has no value; nothing here is estimated except the zone.
Growth
- Growth habit
- Forb/herb
- Duration
- Perennial
- Mature height
- 6 ft
- Growth rate
- Moderate
- Growth form
- Single Crown
- Shape
- Erect
- Lifespan
- Long
- Active growth period
- Spring and Summer
Light and water
- Shade tolerance
- Intolerant (full sun (shade-intolerant))
- Moisture use
- Medium water use
- Drought tolerance
- Low
- Tolerance of waterlogged soil
- Low
- Precipitation range
- 16 to 30 in per year
Soil
- Soil textures
- Coarse, medium and fine
- pH range
- 5 to 7
- Lime (CaCO₃) tolerance
- Medium
- Salinity tolerance
- None
- Fertility requirement
- Medium
- Minimum root depth
- 18 in
Climate
- Minimum temperature
- −33°F
- Estimated cold hardiness
- Zone 4a and warmer
- Minimum frost-free days
- 90
- Fire tolerance
- High
Flowers, leaves and fruit
- Flower color
- White
- Showy flowers
- Yes
- Bloom period
- Early Summer
- Foliage color
- Green
- Showy in fall
- No
- Keeps leaves
- No
- Fruit color
- Black
Other
- Toxicity
- Slight
- Nitrogen fixation
- None
- Nursery availability
- Routinely Available
- Family
- Asclepiadaceae
- PLANTS symbol
- ASSP
Source & data date
- Source
- USDA NRCS PLANTS Database: county distribution records, native status and plant characteristics. CC0 (public domain dedication, per the data.gov catalog record).
- Kew’s World Checklist of Vascular Plants (WCVP): native or introduced status by state. CC BY 3.0.
- USGS US-RIIS (ver. 2.0): species listed as introduced are excluded. CC0.
- Citation
- USDA, NRCS. 2026. The PLANTS Database (https://plants.usda.gov, 11/04/2026). National Plant Data Team, Greensboro, NC USA.
- Govaerts R. (ed.) (2026). WCVP: World Checklist of Vascular Plants. Facilitated by the Royal Botanic Gardens, Kew. Data file dated 2026-06-04, http://sftp.kew.org/pub/data-repositories/WCVP/ (retrieved 2026-11-04). Paper: Govaerts R. et al. (2021) The World Checklist of Vascular Plants, a continuously updated resource for exploring global plant diversity. Scientific Data 8, 215.
- Data date
- Retrieved from PLANTS on November 4, 2026; WCVP data file dated June 4, 2026.
- Scope
- Asclepias speciosa (PLANTS symbol ASSP).
- Method
- A species is listed when it is recorded as native to the state in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in the county by USDA PLANTS. Species PLANTS labels both native and introduced are listed separately. Full method · All sources