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Asclepias syriaca
Also called Silkweed, Silky Milkweed, Kansas Milkweed, Silky Swallowwort, Virginia Silk, Broadleaf Milkweed, Butterfly Flower
Common milkweed is a clonal perennial wildflower native to eastern North America, grown for its fragrant flowers and as a critical food plant for monarch butterfly caterpillars. It spreads by underground roots, so give it room or a contained spot.
Asclepias syriaca, commonly called common milkweed, butterfly flower, silkweed, silky swallow-wort, and Virginia silkweed, is a species of flowering plant. It is native to southern Canada and much of the United States east of the Rocky Mountains, excluding the drier parts of the prairies. It is in the genus Asclepias, the milkweeds. It grows in sandy soils as well as other kinds of soils in sunny areas.
A. syriaca can become aggressive. It spreads from propagative roots and may not be suited to small gardens and formalized plantings. The plant is winter hardy in USDA zones 3–9; it has a preference for moist but well drained soils, but is tolerant of dry conditions and clay soils. Although A. syriaca grows best in full sun, it can tolerate light shade but may produce fewer flowers under such conditions. It is ideal in semi-dry places where it can spread without presenting problems for other ornamental species.
Monarch Watch provides information on rearing monarchs and their host plants. Efforts to restore falling monarch butterfly populations by establishing butterfly gardens and monarch migratory "waystations" require particular attention to the target species' food preferences and population cycles, as well to the conditions needed to propagate and maintain their food plants.
Within its range, A. syriaca can be found in a broad array of habitats from croplands, to pastures, roadsides, ditches, and old fields. More than 450 insect species feed on the plant, including flies, beetles, ants, bees, wasps, and butterflies. It is among the most important food sources for monarch butterfly (Danaus plexippus) caterpillars in the northeastern and midwestern United States and is one of only three milkweed species on which the eastern monarch migration largely depends. Using cardenolide fingerprinting analysis, investigators have found that 85-92% of monarchs overwintering in Mexico had fed on A. syriaca as caterpillars.
The plant's latex contains large quantities of cardiac glycosides, making the leaves and stems of old tall plants toxic to humans and large animals. The young shoots, young leaves, flower buds and immature fruits are all edible raw.
Cartwheels · Whitestem milkweed · Spider milkweed · California milkweed · Heartleaf milkweed · Bloodflower · Curtiss' milkweed · Woollypod milkweed · Desert milkweed · Poke milkweed · Mexican whorled milkweed · Florida milkweed
Text excerpted from the Wikipedia article Asclepias syriaca by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
