# Slim Milkweed (Asclepias linearis)

> A Texas endemic of coastal and blackland prairie, wiry and many-stemmed, with thread-fine opposite leaves and small greenish-white flowers. Known from the middle and upper Gulf Coast north to the Dallas area and nowhere else in the United States.

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

## Summary

A Texas endemic of coastal and blackland prairie, wiry and many-stemmed, with thread-fine opposite leaves and small greenish-white flowers. Known from the middle and upper Gulf Coast north to the Dallas area and nowhere else in the United States.

## Key facts

| Field | Value |
| --- | --- |
| Scientific name | Asclepias linearis Scheele |
| Genus | Asclepias |
| Family | Apocynaceae |
| Common names | Slim Milkweed |
| Status | Native |
| Height | 8 in–1.7 ft |
| Spread | 8 in–1.3 ft |
| Flower color | white, green |
| Bloom period | May to November |
| Light | Full sun |
| Soil moisture | Dry, Average |
| USDA zones | 8-10 |
| Leaf arrangement | opposite |
| Leaf shape | threadlike |
| Sap | Milky latex |
| Root system | Deep taproot, resents transplanting |
| Seed stratification | 30 days cold-moist |
| Monarch value (0-5) | 3 |
| Garden value (0-5) | 2 |
| Nectar value (0-5) | 2 |
| US states recorded | Texas |

## Identification

- Thread-fine linear leaves only 1 to 4 mm wide and 3 to 9 cm long, stalkless or nearly so.
- Leaves are opposite, not in whorls. This is the main separation from whorled milkweed, which carries them in rings of four to six.
- Slender erect stems, usually several from the base, 20 to 50 cm tall.
- Small greenish-white flowers, occasionally brownish or purple-tinged, with a white gynostegium.

## Ecology

A prairie specialist on the Texas Gulf Coast, where almost all of its habitat has been lost to agriculture and development. It flowers over a long season from late spring into autumn, which makes it useful to monarchs on both legs of the migration through Texas.

## Growing

Rarely offered, and then only by Texas native-plant nurseries. Needs full sun and sharp drainage, and dislikes winter wet.

## Cautions

Standard milkweed cautions. A narrowly distributed endemic; buy nursery-grown plants rather than collecting from the wild.

## Questions

**Is slim milkweed the same as whorled milkweed?**

No, though they look alike at a glance and both have thread-fine leaves. Whorled milkweed (Asclepias verticillata) carries its leaves in whorls of four to six around the stem and grows across most of the eastern and central United States. Slim milkweed has opposite leaves and grows only in Texas.

**Is Asclepias linearis native to Maryland?**

No. The USDA PLANTS database lists it for Maryland, but every flora treats it as a Texas endemic reaching into Tamaulipas in northeastern Mexico, and GBIF holds no Maryland records. Treat the USDA entry as an error.

## References



## Photographs

- Slim Milkweed photographed in Brazoria County, TX, USA (Michelle W. （鍾偉瑋）, CC BY 4.0): https://www.inaturalist.org/observations/33462458
- Slim Milkweed photographed in Lewisville, TX, US (Haley Daniels, CC BY 4.0): https://www.inaturalist.org/observations/92818823
- Slim Milkweed photographed in Brazoria County, TX, USA (Wendy McCrady, CC BY 4.0): https://www.inaturalist.org/observations/89601828
- Slim Milkweed photographed in Reseda Dr, Houston, TX, US (Rich Sommer, CC BY 4.0): https://www.inaturalist.org/observations/93318852
- Slim Milkweed photographed in Chambers County, TX, USA (Public domain (CC0), CC0): https://www.inaturalist.org/observations/276211877
- Slim Milkweed photographed in Robstown County Park, Robstown, Texas (Sam Kieschnick, CC BY 4.0): https://www.inaturalist.org/observations/8536617
- Slim Milkweed photographed in Cameron, Texas, United States (Reid Hardin, CC BY 4.0): https://www.inaturalist.org/observations/163417159
- Slim Milkweed photographed in US-181 N, Sinton, TX, US (Chet Burrier, CC BY 4.0): https://www.inaturalist.org/observations/317346798

## How to cite

Milkweed USA. (2026). Slim Milkweed (Asclepias linearis). https://milkweedusa.com/species/slim-milkweed/