Antelope Horns, Spider milkweed, Green-flowered milkweed, Spider antelope-horns Asclepiadaceae (Milkweed Family) Synonym(s): USDA Symbol: ASAS USDA Native Status: L48. Asclepias asperula is a clump-forming, 1-2 ft. perennial with an upright or sprawling habit. Stems are densely covered with minute hairs.
Asclepias californica is native to California and northern Baja California. It is a flowering perennial with thick, white, woolly stems which bend or run along the ground. The plentiful, hanging flowers are rounded structures with reflexed corollas and starlike arrays of bulbous anthers.
Butterfly weed plants (Asclepias tuberosa) are trouble-free North American natives that produce umbels of bright orange, yellow or red blooms all summer long. Butterfly weed is appropriately named, as the nectar- and pollen-rich flowers attract hummingbirds and hordes of butterflies, bees and other beneficial insects throughout the blooming season.
The shape of the cluster, number of flowers per cluster, and flower color are good indicators of species, though it is a pretty safe bet it is not clasping milkweed. If it is a milkweed, chances are it is just common milkweed with some growth anomaly.
"Narrowleaf Milkweed is native to California, Nevada, Oregon, and Washington. I’ve seen it growing wild all over the place! I’ve seen it along the coast in Santa Barbra, along highway 5 from Bakersfield all the way to Seattle and outside the entrance of Yosemite at over 6,000 feet.
Asclepias speciosa is a native milkweed for the western half of US and Canada. This milkweed has a long bloom period and is host/nectar plant for monarchs. Asclepias speciosa is a native milkweed for the western half of US and Canada.
Whorled Milkweed Asclepias verticillata Milkweed family (Asclepiadaceae) Description: This perennial herbaceous plant is ½–2' tall and more or less erect; it is either unbranched or sparingly branched along the upper half of its central stem. The central stem is yellowish green or medium green and terete; it has vertical lines of short pubescence.