652 Asclepias curassavicaCommon Names: scarlet milkweed, bloodflower, silkweed, Indian root Family: Asclepiadaceae (milkweed Family)
Scarlet milkweed is an erect, evergreen perennial subshrub, often grown as an annual. Like most milkweeds, it has opposite leaves and milky sap. The leaves are about 5 in (12.7 cm) long, narrowly elliptic, and pointed at both ends. Scarlet milkweed gets about 3-4 ft (0.6-0.9 m) tall and usually has a few pairs of symmetrical branches. The flowers are orange and red and borne in terminal and axillary clusters that are 2-4 in (5.1-10.2 cm) across. It blooms continuously from spring until autumn. The fruits are spindle shaped pods, 3-4 in (7.6-10.2 cm) long, that eventually split open to release little flat seeds that drift away on silky parachutes. A cultivar with yellow flowers is available.
Scarlet milkweed, Asclepias curassavica is native to South America but has become a naturalized weed in tropical and subtropical pastures, fields and disturbed areas throughout the world, including central and southern Florida.
CultureScarlet milkweed is easy to grow, thriving in dry, moist, and even wet soils. The leaves are sometimes attacked by aphids which produce an excrement (called honeydew!) which is in turn colonized by a grayish black fungus called sooty mold. None of this is life-threatening to the milkweed, and eventually some other predators (such as ladybugs) will come along and polish off the aphids. If you do want to intervene in nature's drama, the aphids are easily washed off with a stream of water or suffocated with horticultural oil or a mild solution of dishwashing detergent. Light: Full sun to partial shade. Moisture: Regular garden watering is adequate. Scarlet milkweed does fine without supplemental watering in the eastern US. Hardiness: USDA Zones 8 - 11. Scarlet milkweed remains evergreen in zones 9B-11, but if it does freeze to the ground, it usually comes back in spring. In cooler climates it can be grown as an annual. Propagation: Scarlet milkweed can be started from cuttings, and it grows quickly from seed.
Use scarlet milkweed in perennial borders and meadow gardens. Its dependable bright orange and red flowers stand out against the dark green foliage. Scarlet milkweed is a thin, unobtrusive little plant that can be squeezed in among other perennials and shrubs and still counted on to show off its pretty flowers. Butterflies and other nectar-sipping insects are attracted to the blossoms, and both monarch and queen butterflies lay their eggs on scarlet milkweed (as well as on other milkweeds, including the southeastern native, butterflyweed, A. tuberosa). The dried pods are used in arrangements.
Most flowers have a ring of sepals, collectively called a calyx, and above that a ring of petals, collectively called a corolla. The milkweeds have an additional ring of appendages that sits above the corolla like a crown; it is called a corona. Daffodils (Narcissus spp.) have a corona, too. In scarlet milkweed, the corolla is usually crimson and the corona is orange.
All milkweeds are poisonous if ingested, and the milky sap is a skin irritant. The butterflies whose caterpillars feed on milkweeds contain the same poisonous glycosides and are poisonous as well.
Steve Christman 3/16/00; updated 1/21/04