Asclepias syriaca - 100 Seed Pack - Evergreen Perennial Flowering Butterfly Shrub - New

Asclepias, the milkweeds, is a genus of herbaceous perennial, dicotyledonous plants that contains over 140 known species. Pollination in this genus is accomplished in an unusual manner. Pollen is grouped into complex structures called pollinia (or "pollen sacs"), rather than being individual grains or tetrads, as is typical for most plants. The feet or mouthparts of flower-visiting insects such as bees, wasps and butterflies, slip into one of the five slits in each flower formed by adjacent anthers. The bases of the pollinia then mechanically attach to the insect, pulling a pair of pollen sacs free when the pollinator flies off, assuming the insect is large enough to produce the necessary pulling force (if not, the insect may become trapped and die). Pollination is effected by the reverse procedure in which one of the pollinia becomes trapped within the anther slit.

Asclepias syriaca commonly known as Com Flower, Silkweed, Silky Swallow-wort and Virginia Silkweed is a milkweed that has fascinating two-tiered vivid flowers arrayed in a dense umbel. A five-pointed star or horn-like stamens comprises the upper tier, while the lower tier consists of the petals which bend backward or downward. The 90cm to 120cm tall milky sapped plants spread from an underground root system. They bloom from early to mid-summer. This plant differs from Showy Milkweed (A. speciosa) in having an unbranched stem. The plant contains cardiac glycosides allied to digitalins used in treating some heart disease. These glycosides when absorbed by monarch butterfly larvae whose sole source of food is milkweed foliage make the larvae and adult butterflies toxic to birds and other predators. A good choice for your large butterfly garden or wildflower meadow. The plant attracts butterflies, bees, and hummingbirds.