Common Milkweed

Growing Conditions

Growing Zones

Thrives in USDA Zones 3 - 9

Companion Planting

When to Plant

• Direct Sow

  Direct sow in autumn for natural cold stratification; or cold-stratify seed 30 days and spring-sow when soil reaches 65°F

• Harvest

  Collect seed pods just before they split in autumn; seeds attached to silky floss

Organic Growing Tips

• Leave aphid colonies on stems undisturbed - they are quickly regulated by lady beetles, parasitic wasps, and spiders.

• Do not use pesticides near milkweed; any systemic treatment will be consumed by monarch caterpillars.

• Allow seed pods to open and disperse naturally; the wind-carried seeds colonize new areas.

• If spreading must be managed, remove rhizome offshoots at the edges of the colony each spring before they establish.

Common Pests

• Aphids
• Milkweed Bug
• Milkweed Beetle
• Milkweed Tussock Moth

Taxonomy

Kingdom

Plantae

Family

Dogbane family (Apocynaceae)

Genus

Asclepias

Species

syriaca

Natural History

Asclepias syriaca is native to eastern and central North America and was one of the most characteristic plants of the pre-settlement tallgrass prairie and eastern savanna landscapes. The species epithet syriaca is a misnomer - Linnaeus named it in 1753 based on the mistaken belief that specimens had been collected in Syria when they were in fact from North America. The plant is the primary larval host of the monarch butterfly (Danaus plexippus), whose extraordinary multigenerational migration between overwintering sites in central Mexico and summer breeding grounds across eastern North America depends on milkweed availability along the migratory corridor. Monarch populations have declined by an estimated 80-90% since the 1990s, a collapse closely correlated with the widespread adoption of herbicide-tolerant genetically modified corn and soybean crops, which enabled the elimination of milkweed from agricultural fields that had historically served as critical monarch habitat. During World War II, schoolchildren across the US collected milkweed seed pods as a civilian war effort contribution: the silky floss served as a kapok substitute in military life preservers, reportedly filling approximately 1.2 million life jackets.

Traditional Use

Asclepias syriaca was one of the most extensively used plants in the material culture of eastern North American Indigenous peoples, documented in numerous ethnobotanical records for both practical and medicinal purposes across dozens of nations. European settlers adopted some of these uses, and the root appeared in American Eclectic medical literature of the 19th century.

• Iroquois (Haudenosaunee) peoples, documented by Herrick and Waugh - Root

  Iroquois ethnobotanical records document preparation of the root in contexts including kidney-related conditions, prepared as a decoction. Herrick's 1977 compilation of Iroquois plant use and Waugh's earlier fieldwork document multiple applications across different nations of the Haudenosaunee confederacy.

• Ojibwe and Anishinaabe peoples - Root and stems

  Densmore's 1928 ethnobotanical survey of the Ojibwe documents use of milkweed root in preparations for female reproductive health contexts. Stem fibers were used in cordage-making traditions across Anishinaabe communities.

• World War II seed floss collection program - Seed floss

  The US War Production Board organized the collection of milkweed pods by schoolchildren and civilians in 1944 and 1945. The hollow, buoyant seed fibers served as a substitute for kapok in military life preservers. Approximately 5,400 tons of floss were collected, enough to fill approximately 1.2 million life jackets - one of the largest organized civilian uses of a native plant in American history.

All parts of Asclepias syriaca contain cardiac glycosides and are toxic if eaten in quantity, particularly the root and raw sap. Indigenous food use consistently involved thorough cooking of young shoots and pods with water changes. The milky latex sap can cause skin and eye irritation. Monarch caterpillars sequester these glycosides as a chemical defense against predation.

This information is provided for historical and educational purposes only and is not medical advice. Always consult a qualified healthcare professional before making decisions related to your health.

Morphology (Plant Structure & Identification)

• Root System

  Extensive, deep, spreading rhizome system that can extend many feet laterally from the parent plant; rhizomes are the primary mechanism of colony expansion and make the plant very difficult to eradicate once established.

• Stem

  Stout, hollow, erect stems 3 - 5 feet tall; covered in fine hairs; exudes milky latex when broken; typically unbranched.

• Leaves

  Large, oval to oblong, opposite, thick and leathery; pale green above with a silvery-downy underside; 4 - 8 inches long.

• Flowers

  Dense, globe-shaped clusters of fragrant pink to mauve flowers at stem tips and upper leaf axils; bloom June through August.

• Fruit

  Large, warty green pods 3 - 4 inches long that turn brown and split in autumn to release flat brown seeds attached to silky white floss.

Known Varieties

Common cultivars worth knowing

• Straight Species

  Seed-grown common milkweed from wild or cultivated sources; the ecologically most valuable form with the highest monarch butterfly support. Plants vary somewhat in height and flower color from pale pink to rosy mauve.

  Best for: Monarch habitat, pollinator meadows, naturalized areas

• Ice Ballet

  White-flowered selection of common milkweed; otherwise identical in habit and ecology to the straight species.

  Best for: White-themed gardens, visual contrast in pollinator plantings