Description
Asclepias – Milkweed – Silkweed
There are about 110 species of evergreen or deciduous clump or spreading perennials and a few subshrubs rarely shrubs, in this genus. They occur form well-drained sites in scrub or grassland sometimes from marsh lands, wet scrub, and lakeside areas in South Africa and temperate North America and tropical North and South America. They produce narrowly elliptic to lance shaped or ovate alternate sometimes spirally arranged leaves. It bears umbel-like cymes of numerous small flowers up to 1” across. The lobes are arch or bent sharply back to show the unusual upright horn like stamens. The flowers are followed by spindle shaped green fruits that vary in length which ripen to yellowish brown that split open to expose rows of seeds with long silky white hairs thus the common name, silkweed. Their great for attracting bee’s and butterflies, the sap is acrid and poisonous and the butterfly larvae that feed on them are toxic to predators such as birds. There are great for a border, meadow or wildflower gardens. Contact with sap may irritate skin.
Cold hardiness varies greatly between species. These easily grown plants that need fertile, well-drained, loamy soil in full sun. Divide in spring.
Prone to Whiteflies, spider mites, aphids, mealybugs, rust, bacterial leaf spots and fungi leaf spots.
Ascelpias tuberosa – Butterfly Weed – This tuberous, hairy, mounding forming perennial from Eastern and Southern North America grows to 36” tall and spreads to 12” wide. On thick stems it carries numerous spirally arranged lance shaped to oblong-ovate light to mid green leaves up to 5 ½” long. From midsummer to early autumn it bears axillary and terminal umbel-like cymes up to 2” wide of orange sometimes orange-red or yellow flowers. Flowers are followed by fruit 3 ½-5” long on nodding stalks. They’re adaptable to both moist and very dry soils and need full sun and good drainage.
Zones 3-9
