Blood flower, also known as cotton bush, Mexican butterfly weed, and scarlet milkweed, is a tropical perennial subshrub native to South America often grown as an annual in the US where it has become a weed in the Deep South. It is a member of the dogbane family, Apocynaceae, that also includes bluestar (Amsonia), periwinkle (Vinca), and oleander (Nerium). Pale gray stems carry pointed lanceolate leaves up to six inches long sometimes with white midribs. Flowers appear from spring until fall in rounded axillary or terminal clusters two to four inches across. The purple or red petals are complemented by a five hooded corona tipped with yellow or orange. The flowers give way to three to four inch long spindle-shaped seed pods (follicles) that split to release flat brown seeds with silky hairs that facilitate wind dissemination. The flowers are attractive to bees, hummingbirds, and butterflies, and Monarch larvae use it as a host plant. The stems and leaves have a milky sap that is poisonous and may irritate skin and eyes. Suitable for inclusion in meadow and butterfly garden as well as in containers and in the border where its long bloom time will enhance the site for most of the growing season. Good cut flower tropical and seed pods attractive in dried arrangements. The generic name Asclepias comes from the name of the Greek god of medicine. The specific epithet curassavica refers to the island of Curacao, Dutch Antilles, in the Caribbean Sea.
Type: Perennial tropical subshrub
Bloom: Red to purple flowers tipped with yellow or orange in clusters two to four inches across from spring to fall
Size: 2-3’ H x 1.5-2’ W
Light: Full sun; tolerates light shade
Soil: Average, medium moist, well-drained; tolerates some dryness
Hardiness: Zones 9-11; usually grown as an annual
Care: Low maintenance
Pests and Diseases: Aphids
Propagation: Seed, cuttings
Companion Plants: Purple salvia such as ‘East Friesland’ , black-eyed Susan, Gaillardia aristata, yarrow such as ‘Coronation Gold’, lilies, ornamental grass
Outstanding Selection: Yellow cultivars are available.