# Ruth’s Milkweed (Asclepias ruthiae)

> A low, spreading Colorado Plateau milkweed of red sand and slickrock country, with small thick leaves and pale pink-cream flowers held close to the ground among the sandstone.

Source: https://milkweedusa.com/species/ruths-milkweed/  
Licence: CC BY 4.0 (Milkweed USA)

## Summary

A low, spreading Colorado Plateau milkweed of red sand and slickrock country, with small thick leaves and pale pink-cream flowers held close to the ground among the sandstone.

## Key facts

| Field | Value |
| --- | --- |
| Scientific name | Asclepias ruthiae Maguire |
| Genus | Asclepias |
| Family | Apocynaceae |
| Common names | Ruth’s Milkweed |
| Status | Native |
| Height | 4 in–1 ft |
| Spread | 10 in–2 ft |
| Flower color | pink, cream |
| Bloom period | April to June |
| Light | Full sun |
| Soil moisture | Dry |
| USDA zones | 5-9 |
| Leaf arrangement | opposite |
| Leaf shape | ovate |
| Sap | Milky latex |
| Root system | Deep taproot, resents transplanting |
| Seed stratification | 60 days cold-moist |
| Monarch value (0-5) | 2 |
| Garden value (0-5) | 1 |
| Nectar value (0-5) | 2 |
| US states recorded | Arizona, Nevada, Utah |

## Identification

- Prostrate to low-spreading stems radiating from a central taproot.
- Small, thick, blunt leaves, often folded and gray-tinged.
- Pale pink to cream flowers in small clusters near the stem tips.

## Ecology

A sandy-soil specialist of the Colorado Plateau, used by monarchs and queens moving through canyon country in spring.

## Growing

Rarely available. Needs pure sand, full exposure and no summer irrigation.

## Cautions

Standard milkweed cautions.

## References

- Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21286-2
- GBIF: https://www.gbif.org/species/3574177
- iNaturalist: https://www.inaturalist.org/taxa/898625
- Wikipedia: https://en.wikipedia.org/wiki/Asclepias_ruthiae
- BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20ruthiae.png
- NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20ruthiae

## Photographs

- Asclepias ruthiae in flower (Brad Grimm, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_ruthiae_in_flower.jpg
- Asclepias uncialis subsp. ruthiae kz02 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_uncialis_subsp._ruthiae_kz02.jpg
- Asclepias uncialis subsp. ruthiae kz01 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_uncialis_subsp._ruthiae_kz01.jpg
- Ruth’s Milkweed photographed in Emery County, US-UT, US (Parker James Lloyd, CC BY 4.0): https://www.inaturalist.org/observations/349158179
- Ruth’s Milkweed photographed in Utah, US (Kenzie Anderson-Bell, CC BY 4.0): https://www.inaturalist.org/observations/280644260
- Ruth’s Milkweed photographed in Emery, Utah, United States (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/160688515
- Ruth’s Milkweed photographed in Wayne County, US-UT, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/216446370
- Ruth’s Milkweed photographed in Huntington, UT, US (Dee Shea Himes, CC BY 4.0): https://www.inaturalist.org/observations/215572578

## How to cite

Milkweed USA. (2026). Ruth’s Milkweed (Asclepias ruthiae). https://milkweedusa.com/species/ruths-milkweed/