Asclepias vestita, (Woolly Milkweed)
This species is endemic (not found anywhere else) to California. It gained its common name because the leaves are covered with fine white hairs, giving the plant a fuzzy or woolly appearance, a trait common to plants that grow in arid, sunny environments. This plant is similar to A. eriocarpa and A. erosa, but differs from A. eriocarpa in leaf shape. Differs from both species in the position of the umbels that lack peduncles such that the individual flowers are attached directly to the main stem.
Flower: Corolla is usually a cream to yellow color with purple or brown tinge. Hoods and horns are a cream to yellow color. Corolla reflexes backward to expose hoods. Umbels directly attach to the main stem with 10 +/- flowers per umbel. Corolla outer surface is covered with fine hairs, but the hoods, horns, and inside of corollas are hairless. 1-3 umbels per stem.
Foliage: Stands erect to ascending. Covered in fine white-colored hairs. Due to the fine white hairs, its overall color appears to be a grayish green. Leaf arrangement is opposite and attachment is petiolate sometimes sessile.
Growth Period: Spring and Summer.
Habitat: Dry desert slopes and plains.
Height: 1 ½- 3 ft (0.5 – 1 m).
Leaves: Oval to narrow lanceolate with tips typically pointing upward. Leaves are thick and covered with fine white hairs. 2 ¾ – 6 ¾ in (7-17 cm) long.
Blossoming Season: April – June.
Life span: NA
Propagation: By seed.
Pods: Yellowish color. 2 7/16 in (6 cm) long and 1 in (2 1/2 cm) thick. Pedicels are reflexed. Glabrous when mature.
Seed Color: NA
Environment and Growth Requirements
Overhead Conditions: Not shade tolerant, needs full sun.
Precipitation: Less than 10 in to 20 in (25-51 cm) annually.
Soil Texture: This species resides in open fields in the southern half of California in areas that experience winter and spring rainfall followed by hot, dry summer and fall conditions.
Temperature: Can tolerate a minimum temperature of 10 to 20 Fahrenheit (-12 to -6 Celsius).
Work Cited: wikipedia.org, Plants.usda.gov, laspilitas.com, davesgarden.com, Arborday.org, Eduplace.com