Culture
Easily grown in average, dry to medium moisture, well-drained soils in full sun. Drought tolerant. Easily grown from seed, and will self-seed in the landscape if seed pods are not removed prior to splitting open. Plants will also spread by rhizomes, but are not considered to be invasive.
Noteworthy Characteristics
Asclepias viridis, commonly called green or green-flowered milkweed, is an erect to sometimes decumbent glabrous perennial that grows to 20-30" tall on usually upright stems clad with mostly alternate, short-stalked, pointed, ovate-lanceolate, pale green leaves (to 2-5” long). Stems and leaves exude a milky sap when cut or bruised. It is native to glades, prairies, pastures, fields and roadsides from Ohio to Nebraska south to Florida and Texas. Tiny green flowers with purple hoods bloom in many-flowered axillary and terminal umbels from May to June. Each tiny flower (to 1” long) has 5 upright pale green corolla lobes (petals) and 5 purple hoods. Horns are absent. Flowers give way to seed pods (to 5” long) which split open when ripe releasing numerous silky-tailed seeds for dispersal by the wind. Seed pods are valued in dried flower arrangements. Flowers are a nectar source for many butterflies, and leaves are a food source for monarch butterfly larvae (caterpillars).
The charismatic and imperiled monarch butterfly requires milkweed plants in order to survive. Monarchs migrate into the eastern U.S. from Mexico in spring to lay their eggs on milkweed species plants. Caterpillars hatch from the eggs and consume the milkweed plant foliage as food for growth and development. Mature caterpillars will search for a nearby, sheltered location to enter the pupal stage and form a chrysalis. Inside, they will complete metamorphosis and emerge as an adult butterfly in around 2 weeks. Flower nectar is consumed by adult butterflies as a valuable food source. The 4th or 5th generation of monarch butterflies that emerges in August-September will migrate into Mexico to overwinter as adults. Significant declines in monarch butterfly populations in North America over the course of the 21st century are believed by many experts to be caused by a reduction in milkweed due to widespread use of herbicide-tolerant row crops, climate change, and loss of overwinter sites due to habitat destruction.
To support monarch butterflies, plant species of milkweed that are native to your area.
Genus name honors the Greek god Asklepios the god of medicine.
Specific epithet from Latin means green in reference to flower color.
Many common names of this species refer to the green color of the flowers. Additional common names include green antelope horn (curved seedpod resembles an antelope horn) and spider milkweed (white crab spider lives on this plant).
Problems
No serious insect or disease problems. Aphids can be problematic but attempting to control them can result in inadvertent harm to monarch caterpillars and other beneficial insects.
Uses
Butterfly gardens, meadows, prairies, or naturalized/native plant areas. Borders.