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Asclepias curassavica Butterfly Weed, Milkweed, Silkweed1

Edward F. Gilman, Ryan W. Klein, and Gail Hansen 2


Butterfly weed is a member of the milkweed family and, by some reports, the only Asclepias that does consistently well in south Florida. 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. Full form—Asclepias curassavica: butterfly weed, milkweed, silkweed.
Figure 1.  Full form—Asclepias curassavica: butterfly weed, milkweed, silkweed.
Credit: Edward F. Gilman, UF/IFAS

Figure 2. Leaf—Asclepias curassavica: butterfly weed, milkweed, silkweed.
Figure 2.  Leaf—Asclepias curassavica: butterfly weed, milkweed, silkweed.
Credit: Edward F. Gilman, UF/IFAS

Figure 3. Flower—Asclepias curassavica: butterfly weed, milkweed, silkweed.
Figure 3.  Flower—Asclepias curassavica: butterfly weed, milkweed, silkweed.
Credit: Edward F. Gilman, UF/IFAS

General Information

Scientific name: Asclepias curassavica

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

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

Family: Apocynaceae

Plant type: herbaceous; annual

USDA hardiness zones: 4 through 10 (Figure 4)

Figure 4. Shaded area represents potential planting range.
Figure 4.  Shaded area represents potential planting range.

Planting months for zone 7: June; July

Planting months for zone 8: May; June; July; August

Planting months for zone 9: March; April; May; June; July; August; September

Planting months for zone 10 and 11: February; March; April; May; June; July; August; September; October; November; December

Origin: native to Central America, North America, Mexico, and South America

Invasive potential: Caution—may be recommended by UF/IFAS faculty but should be managed to prevent its escape (reassess in 2 years)

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

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


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 tolerance: 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

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. Occasional fertilization can help keep flowers coming nearly all year long.

Design Considerations

The thin stems and widely spaced leaves of the butterfly weed give a slightly weedy appearance (hence the name), so most gardeners mix them with shorter plants where the bright red and yellow flowers can be easily seen above the ground cover. The leaves can be stripped by caterpillars and the plant often looks stick-like at certain times of the year so using ground cover also helps hide the bare stems until they can be cut back. Pair with plants with large foliage and mounding or loose spreading forms to help the butterfly weed poke through the plants. White or purple flowers are complementary colors to yellow and red, which will contrast nicely.

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.


1. This document is FPS-49, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date October 1999. Revised August 2018. Visit the EDIS website at for the currently supported version of this publication.
2. Edward F. Gilman, professor, Environmental Horticulture Department; Ryan W. Klein, graduate assistant, Environmental Horticulture Department; and Gail Hansen, associate professor, Environmental Horticulture Department; UF/IFAS Extension, Gainesville, FL 32611.

Publication #FPS-49

Date: 12/4/2018

      Organism ID


      • Gail Hansen de Chapman