(Asclepias asperula)
Spider Antelope Horns Milkweed

Spider Antelope Horns milkweed (Asclepias asperula), a member of the Apocynaceae (Dogbane Family), is a herbaceous perennial that grows from 1 to 3 feet tall and has greenish-white, greenish-yellow, yellow to sometimes purple flowers that bloom from the spring through fall (roughly April to September, depending on location). The flowers in a cluster look like tennis balls. The leaves are simple, opposite, entire, lanceolate to linear-lanceolate in shape and are 4-8 inches in length and 0.25-3 inches wide. The clusters of fruits look like a herd of antelopes. This plant grows in zones 4-9 and likes open areas with full sun that have dry to medium well-drained soil.  More information on this species can be found on this blog post.