Asclepias pumila aka Dwarf Milkweed

Asclepias pumila is a small perennial, a plant that lives for years. It belongs to the Apocynaceae family. People call it low milkweed or plains milkweed. It comes from the central and west-central United States. It grows in the Dakotas, Nebraska, Kansas, and Oklahoma. Its range also spans Colorado, Wyoming, Montana, and New Mexico. It reaches northern Texas, too. It grows in temperate regions and on open prairies. Wild sites have sand, clay, or rocky ground. Some soils hold lime or gypsum.

The plant grows about 1.3 feet (0.4 metres) tall. Its low height suits the front of garden beds. The supplied species account gives no spread at full size. Flowers bloom from July to August. Each has both male and female organs. Bees, butterflies, moths, and other insects pollinate them. They move pollen between flowers. Seeds ripen from August through October, after the summer bloom. PFAF notes its use for drawing wildlife. Its value to bees adds a reason to grow it.

PFAF advises sun and soil that drains well for garden use. The plant also grows in light shade. Sand and loam suit it. Soil can be mildly acid, neutral, or mildly alkaline. The account lists both dry and moist soil as suitable. Its growing notes also favour moist, rich, light or peaty soil. These notes give a range of soil moisture needs, not one fixed choice. PFAF lists USDA zones 5–9 and UK zone 6. That UK zone is not an RHS hardiness rating.

Plant young plants where they will stay. Their roots dislike disturbance. You can raise new plants from seed. PFAF suggests sowing fresh seed in autumn or late winter. Stored seed may need two to three weeks of cold treatment. Seeds take one to three months to sprout at about 18°C. Grow the young plants under glass through their first winter. Plant them out in late spring or early summer, during active growth. Take care when dividing plants in spring to avoid root damage.

Safety limits its use beyond the flower bed. PFAF reports that this species can poison livestock. Its food-use notes draw on other milkweeds. They do not confirm food uses for this species. Nor do they show which parts are safe to eat. PFAF also records a traditional leaf infusion for diarrhoea. That record does not show it is safe or prove it works.