Species Native to Missouri
Common Name: whorled milkweed
Type: Herbaceous perennial
Family: Apocynaceae
Native Range: United States
Zone: 4 to 9
Height: 1.00 to 2.50 feet
Spread: 1.00 to 2.00 feet
Bloom Time: June to September
Bloom Description: White
Sun: Full sun to part shade
Water: Dry to medium
Maintenance: Low
Suggested Use: Naturalize
Flower: Showy
Attracts: Hummingbirds, Butterflies
Tolerate: Deer, Drought, Dry Soil
Culture
Easily grown in average, dry to medium moisture, well-drained soils in full sun. Tolerates part shade. Best in sunny locations with sandy loams. Drought tolerant. Easily grown from seed, and will self-seed in the landscape if seed pods are not removed prior to splitting open. Likes hot dry soils, but tolerates moist garden soils. Plants will spread by rhizomes but are not considered invasive.
Noteworthy Characteristics
Asclepias verticillata, commonly known as whorled milkweed, is an upright perennial that typically grows to 2.5’ tall on simple, usually unbranched stems clad with long, narrow, sessile, needle-like, linear leaves (each 2-3” long) with revolute margins arranged in whorls of 3 to 6 at each node along the length of the stems. Stems ooze a milky sap when cut or broken. This plant is native to glades, dry prairies, dry slopes, dry open woods, pastures, fields and roadsides in a large part of central and eastern North America extending from Massachusetts to Ontario and Saskatchewan south to Arizona and Florida. In Missouri it is commonly found throughout the State except in the bootheel area.
Flowers bloom in small clusters (umbellate cymes of 3-20 flowers) in the upper leaf axils and stem ends between June and September. Flowers are fragrant. Each tiny flower (to 1/4” long) has a 5 lobed calyx, 5 greenish-white corolla lobes and 5 white hoods with incurved horns protruding from each hood. Flowers give way to smooth, narrow seed pods (to 3” long) which split open when ripe releasing numerous silky-tailed seeds for dispersal by the wind.
Seed pods are valued in dried flower arrangements.
Monarch butterflies need milkweed plants (Asclepias genus) in order to survive. Monarchs lay their eggs on milkweed plants, caterpillars hatch from the eggs and consume the plant foliage as food for growth and development, and the flower nectar is consumed as a valuable source of food by adult monarchs. Recent significant declines in monarch butterfly populations in North America are believed by many experts to be related to a corresponding significant decline in milkweed plants which in large part has been caused by an increased use of glyphosate herbicides around food crop areas where glyphosate-tolerant (Roundup Ready) crops are being grown.
Genus name honors the Greek god Asklepios the god of medicine.
Specific epithet comes from the Latin word verticillatus meaning whorled in reference to the leaves appearing in whorls.
Common name suggests this plant is noted for its whorled leaves and milky sap. Additional common names for this plant include horsetail milkweed.
Problems
No serious insect or disease problems. Aphids.
Uses
Butterfly gardens, meadows, prairies, or naturalized/native plant areas. Borders.