Asclepias ovalifolia aka Oval Leaf Milkweed

Asclepias ovalifolia is known as oval-leaf milkweed. This perennial lives for more than two years. It belongs to the Apocynaceae family. Its native range spans southern Canada and the northern United States. Records place it in Saskatchewan, Illinois, Iowa, Minnesota, and Wisconsin. It grows in regions with a temperate climate. It lives in both prairies and woods. Wild plants grow in sand, gravel, or clay-rich soil. Sites range from open ground to light shade in woods.

Plants reach about 2 feet [0.6 metres] tall. They can spread about 3.3 feet [1 metre] wide. Their spread can thus exceed their height. PFAF lists the plant for use in garden beds. That source gives its bloom time as July through August. Seeds ripen from August through October. Each flower has both male and female organs. Bees and other insects help pollinate the blooms. Moths and butterflies do so too. The plant has value in beds that draw wildlife.

Choose light soil that drains well to grow this plant. Sand and loam suit it. PFAF also suggests rich soil or soil with peat. Its advice covers soil from dry to moist. Some advice it cites puts more stress on moist ground. The plant does well in sun but accepts part shade. It tolerates mildly acid soil. Neutral and mildly alkaline soils suit it too. PFAF lists USDA hardiness zones 5–9. Choose the site with care. Disturbing the roots can harm the plant.

You can raise new plants from seed. Sow fresh seed under glass in autumn or late winter. PFAF also notes success when sown in early spring. Stored seed may need two to three weeks of cold treatment. At 18°C, seeds may take one to three months to sprout. Move each seedling to its own pot when large enough to handle. Keep them under glass for their first winter. Plant them out while they grow in late spring or early summer. Take care when dividing plants in spring to limit root damage. PFAF says to guard young plants from slugs as they take root.

Evidence on food use and safety for this species remains scarce. PFAF draws its detailed food claims from a different milkweed species. Those claims do not show that oval-leaf milkweed is safe to eat. Its hazard notes also lack reports for this species. PFAF lists no known uses in medicine.