Asclepias viridis, (Green Antelopehorn Milkweed)
General Description
This milkweed is common in pastures from Kansas to Texas. Generally avoided by cattle and horses. It can be found along roadsides, ditches, prairies, open areas, and other areas with little vegetative competition. This species tends to be short (12 inches) with multiple stems emerging from the root crown of mature plants. Taller, more erect plants, usually with one or a few stems, can be found in moist prairies. Leaf shape is highly variable. The yellow-white flowers are borne on large erect umbels. The flowers are distinct in that they lack horns.
Form/Growth
Distribution: AL, AR, FL, GA, IL, IN (Endangered), KS, KY, LA, MO, MS, NE, OH, OK, SC, TN, TX, WV
Flower: Usually one umbel per stem but large plants may have up to 10 stems and infloresences, 3-5 in (7 ¾ -12 ¾ cm) wide with 10 +/- flowers per umbel. Color is white to yellow-green with a purple tinge. Corolla is green or cream. Hoods are purple to white. Corolla cups upward and around the outside of the hoods. Doesn’t have horns.
Foliage: Stems are ascending. Glabrous but foliage has a course texture. Leaf arrangement is alternate to sub-opposite and attachment is petiolate with short petioles. Will form several pods per stem. One umbel to a stem, occasionally two.
Habitat: Dry areas, prairies, pastures, glades, ditches, disturbed ground, limestone soils.
Height: 9 ¾ – 25 ½ in (25-65 cm).
Leaves: Ovate to lanceolate, 2-4 ¾ in (5-12 cm) long and 3/8- 2 ¼ in (1-5 ½ cm) wide. Glabrous, but occasionally has fine sparse hairs.
Roots: Taproot.
Toxicity: Low.
Reproductive
Blossoming Season: May – August.
Life span: NA
Propagation: By seed.
Pods: Usually erect, 2 ½ -5 in (6-13 cm) long and ½ – ¾ in (1-2 cm) wide. Slightly hairy.
Seed Color: Brown.
Environment and Growth Requirements
Maintenance: Low.
Overhead Conditions: Open spaces with lots of sunlight.
Precipitation: 20-60 in (51-153 cm) annually.
Soil Texture: Sandy or rocky soils.
Temperature: Can withstand a minimum temperature of -20 to 0 Fahrenheit (-29 to -18 Celsius).
Work Cited: kswildflower.org, Plants.usda.gov, dnr.state.oh.us, Arborday.org, Eduplace.com, critsite.com
Photos: Monarch Watch Archive
