DATE: 09/08/05

CONTACT: Home & Garden Information Center, 1-888-656-9988

WRITER: Anthony Keinath, Plant Pathologist, Clemson University

BLOODFLOWER MILKWEED—BEAUTIFUL ALL SUMMER, GLORIOUS IN AUTUMN

CLEMSON – Bloodflower milkweed is one of three native milkweeds available to Carolina gardeners. Bloodflower milkweed (Asclepias curassavica), butterfly weed (A. tuberose), and swamp milkweed (A. incarnata) have flowers of similar shape but in different colors that attract butterflies, especially monarchs. Bloodflower milkweed and butterfly weed plants are available in garden centers, but swamp milkweed usually is available only from seed companies.

The flower heads, called umbels, are groups of flat-topped clusters of six to nine individual flowers. Flowers form regularly from mid-summer until frost. Bloodflower milkweed plants grow throughout the season by extending the main stem to one side of a flower cluster.

Bloodflower milkweed 'Silky Gold'

One to three seed pods may form per umbel. Pods are filled with brown seeds with silky tails that help the seeds spread by wind. It is usually best to remove seed pods before they burst open and scatter the seeds. “Self-sown” seedlings usually do not grow fast enough to bloom the same season. Some seed will sprout the following year, but these plants also do not bloom reliably.

Bloodflower milkweed is a very tender perennial that does not survive winters above USDA zone 9. However, as with most plants that self-sow, it is easy to grow from seed that can be saved from existing plants. Plants take 8 to 10 weeks to flower from sowing.

Start seedlings indoors about six weeks before the last frost, but do not plant them until at least two weeks after the frost-free date to allow temperatures to warm a bit. Water seedlings or plants regularly for two weeks after transplanting to help them establish.

Bloodflower milkweed ‘Silky Gold’

Bloodflower milkweed prefers full sun but also will flower in part sun. It prefers moist soil, but will tolerate wet or dry periods. Plants will drop lower leaves if they are too dry. At planting, add slow-release fertilizer or compost to the soil. If the leaves begin to turn pale green later in the season, apply half-strength liquid fertilizer.

Bloodflower milkweed is deer-resistant. Its only pest is aphids that feed on the flowers and the undersides of upper leaves. Aphids can be controlled easily with insecticidal soap, but they likely will reappear once or twice during the season. Do not use chemical insecticides that would kill butterflies or monarch butterfly larvae that feed on the plants.

For answers to your gardening, pest and food safety questions, visit the Clemson Extension Home & Garden Information Center website at http://hgic.clemson.edu or call us toll-free at 1-888-656-9988.

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