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Publication #FPS-49

Asclepias curassavica Butterfly Weed, Milkweed, Silkweed1

Edward F. Gilman2


Butterfly weed is a member of the milkweed family, and by some reports, the only Asclepias that does consistently well in south Florida (Figure 1). The plant can be grown as an annual flower or as a perennial. The plants grow to two- to four-feet-tall and flower from spring until fall. The flower colors are red and orange borne in clusters at the top of the plant. Butterflies can usually be seen flying around the plant and visiting the flowers.

Figure 1. 

Butterfly weed.

[Click thumbnail to enlarge.]

General Information

Scientific name: Asclepias curassavica

Pronunciation: ass-KLEE-pee-us kur-uh-SAV-ick-uh

Common name(s): butterfly weed, milkweed, silkweed

Family: Asclepiadaceae

Plant type: herbaceous; annual

USDA hardiness zones: 4 through 10 (Figure 2)

Planting month for zone 7: Jun; Jul

Planting month for zone 8: May; Jun; Jul; Aug

Planting month for zone 9: Mar; Apr; May; Jun; Jul; Aug; Sep

Planting month for zone 10 and 11: Feb; Mar; Apr; May; Jun; Jul; Aug; Sep; Oct; Nov; Dec

Origin: not native to North America

Uses: naturalizing; cut flowers; attracts butterflies; mass planting

Availability: somewhat available, may have to go out of the region to find the plant

Figure 2. 

Shaded area represents potential planting range.

[Click thumbnail to enlarge.]


Height: 1 to 2 feet

Spread: 1 to 2 feet

Plant habit: round; upright

Plant density: moderate

Growth rate: fast

Texture: medium


Leaf arrangement: alternate

Leaf type: simple

Leaf margin: entire

Leaf shape: oblong

Leaf venation: parallel

Leaf type and persistence: deciduous

Leaf blade length: 4 to 8 inches

Leaf color: green

Fall color: not applicable

Fall characteristic: not applicable


Flower color: red; yellow

Flower characteristic: summer flowering; spring flowering


Fruit shape: unknown

Fruit length: unknown

Fruit cover: unknown

Fruit color: unknown

Fruit characteristic: inconspicuous and not showy

Trunk and Branches

Trunk/bark/branches: not applicable

Current year stem/twig color: green

Current year stem/twig thickness: thick


Light requirement: plant grows in full sun

Soil tolerances: acidic; slightly alkaline; sand; loam; clay

Drought tolerance: high

Soil salt tolerances: poor

Plant spacing: 18 to 24 inches


Roots: not applicable

Winter interest: no special winter interest

Outstanding plant: plant has outstanding ornamental features and could be planted more

Invasive potential: may self-seed each year

Pest resistance: very sensitive to one or more pests or diseases which can affect plant health or aesthetics

Use and Management

As plants age and become somewhat woody near the base of the plant, cut them back to stimulate new growth near the bottom. This will help them look good for many years.

The best sites have exposure to sun or partial shade and almost any soil. Butterfly weed is slow to start growth in the spring. Mark its location in hardiness zones 8 and parts of 9 before the plant disappears in the winter to prevent damage to easily injured dormant crowns. A deep root (taproot) reportedly makes transplanting difficult. Once established do not disturb butterfly weed unnecessarily. Ocassional fertilization can help keep flowers coming nearly all year long.

Pests and Diseases

Aphids may infest butterfly weed.

Leaf spot diseases are seen but not serious.

Rusts cause the formation of reddish colored spots.

Cucumber mosaic virus causes leaf mottling but no chemical control is available.



This document is FPS-49, one of a series of the Environmental Horticulture, UF/IFAS Extension. Original publication date October 1999. Reviewed February 2014. Technical revision January 2018. Visit the EDIS website at


Edward F. Gilman, professor, Environmental Horticulture Department; UF/IFAS Extension, Gainesville, FL 32611

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.