Virginia ecotype
Duration: Perennial
Habit: Upright, spreading, naturalizingSize: 2-5 ft. high, half as wide
Flowering time: Jun, Jul, Aug
Bloom color: White to cream-pink
Habitat: Roadsides, open woods, ditches, meadows, abandoned fieldsMoisture: Average to moist, well draining
Light: Full sunSoils: Sand, clay, loam, gravely, well draining
Uses: wild meadows, pollinator gardens, containers
Note: Common milkweed is a vigorous spreader that may not be suitable for small gardens, or may require some planning.
Asclepias syriaca (Common milkweed)
Common milkweed typically grows 2 to 5 feet tall, with thick, upright stems and broad, oval-shaped leaves which are a source of food for Monarch butterfly (Danaus plexippus) caterpillars. In early to mid-summer, milkweed produces large, spherical clusters of fragrant, white to cream-pink flowers that are fragrant and extremely attractive to a wide range of pollinators.
When broken, the stems and leaves release a sticky, white, milky sap. This sap contains toxic compounds called cardenolides (cardiac glycosides), which make Monarch caterpillars, the butterflies, and other insects that dine on the plant distasteful or poisonous to predators.
Sometimes plants are accompanied by little red beetles, Tetraopes tetrophthalmus. These beetles are a specialist native insect and do little to no harm to the plants. Like the monarch, the red milkweed beetle evolved with milkweeds and need the plants to survive and reproduce. The bug's bright red coloring, and the monarch's bright orange appearance is a type of natural warning signal. The coloring warns predators that consuming the bugs as a meal would be unenjoyable due to the milkweed toxins they injested.
The orange Oleander aphids are a non-native insect that parasitises milkweed, but usually doesn't kill them. These aphids can be removed manually, though studies have shown predatory beetles will favor eating the aphids over consuming Monarch caterpillars.
Common milkweed plants prefer moist, well draining sites, but can tolerate average or semi-dry moisture, and a wide range of soil types. The species prefers full sun and doesn't do well in anything less.
In late summer and fall, the plant produces large, spiny seed pods that split open to release silky, windborne seeds, aiding widespread dispersal. Another harmless specialist bug, Oncopeltus fasciatus, the Large Milkweed Bug, feeds on milkweed plants and prefers these seed pods.
Common milkweed plants spread widely underground, sometimes ten feet or more in a single season, to form a colony over time. As such common milkweed may be best for wild gardens or large containers.