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Asclepias curassavica

tropical milkweed

Apocynaceae tropical Americas

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Container Friendly

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 9–11

Overview

Asclepias curassavica is a tender evergreen perennial or subshrub in the dogbane family, grown as an annual in cold climates and reaching 24-36 inches (60-90 cm) tall and 12-24 inches (30-60 cm) wide. Upright stems carry opposite, lance-shaped leaves 3-5 inches (8-13 cm) long and exude a milky white sap when broken. From late spring through autumn the plant bears flat-topped clusters of small flowers, each with five reflexed red to orange petals and a raised yellow-orange central crown. The flowers are followed by slender, pointed seed pods 3-4 inches (8-10 cm) long that split to release flat brown seeds with tufts of silky white hairs. All parts contain cardiac glycosides and are poisonous to people, livestock, and pets if eaten, and the sap can irritate skin and eyes. The plant is a larval host for monarch butterflies and a nectar source for many pollinators. In frost-free regions the foliage persists year-round rather than dying back, which can alter monarch migration timing and allow the protozoan parasite Ophryocystis elektroscirrha to build up on old leaves. Plants self-seed readily in warm climates.

Native Range

Asclepias curassavica is native to tropical regions of the Americas, including Central and South America and the Caribbean. It has naturalized in warm parts of the world, including the southern United States, Africa, Asia, and Australia. It grows in open, disturbed ground, fields, and roadsides.

Suggested Uses

Grown in butterfly and pollinator gardens, mixed borders, and containers, spaced 12-18 inches (30-45 cm) apart. It serves as a larval host for monarchs and a nectar source for bees and butterflies. The cut flowers and seed pods are used in arrangements.

How to Identify

Flat clusters of red-orange flowers, each with a raised yellow central crown, sit atop upright stems with opposite, lance-shaped leaves. Broken stems and leaves release a milky white sap. The slender seed pods open to release seeds carried on silky white floss.

Appearance

Size & Dimensions

Height2' - 3'

Width/Spread1' - 2'

Reaches mature size in approximately 1 years

Colors

Flower Colors

red

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~22 weeks

Spring Summer Fall

Flowering runs from late spring through autumn, and nearly year-round in frost-free climates. The red and orange flower clusters open in succession over many weeks. Seed pods follow and release silk-borne seeds as they dry.

Detailed Descriptions

Flower Description

red-orange with yellow crown

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

loam sand clay

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

tender

Time to Maturity

1 year

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plants grow in full sun and average, well-drained soil, tolerating heat, humidity, and drought once established. They flower over a long season with little care and need no staking. All parts contain cardiac glycosides and are poisonous if eaten, and the milky sap can irritate skin. In USDA zones 9 to 11 the plant is a short-lived perennial that stays evergreen, while in colder zones it is grown as an annual. Where it stays evergreen, cutting stems back in autumn reduces parasite buildup that can affect monarchs. Plants self-seed and can spread in warm regions.

Pruning

Stems can be cut back by half after the first flush to keep plants bushy and prolong bloom. In frost-free areas, cutting plants to 6 inches (15 cm) in late autumn removes old foliage and limits monarch parasite buildup. Removing seed pods before they split reduces self-seeding.

Pruning Schedule

fall