Tropical Milkweed is a tender erect perennial often grown as an annual. It can be weedy in disturbed areas and is frequently found naturalized in waste places, roadsides, or fields. Its bright orange-red flowers form in clusters on top of the leaves and stems that have a milky juice when damaged. Blooming from spring to fall in temperate climates. Plant it in the full sun in moist, fertile, well-drained soil. It will reach a height of 3 feet and a spread of 2 feet. Although milkweed is an important food source for the Monarch butterfly caterpillar, this plant isn't recommended for attracting Monarch Butterflies because they can bloom out of sync with Monarch migration patterns and hold them too long in one area, affecting their populations. Plant one of the native milkweeds instead. In addition to the Monarch, the larvae of the Milkweed Tussock moth ( Euchaetes Egle ) feed on this plant. It will remain as an evergreen to Zone 9b. The long tap root makes it difficult to transplant when mature. Use in naturalized areas, pollinator, rock and cottage gardens. Insects, Diseases, and Other Plant Problems: Aphids are a common insect. They tend to colonize on the plant, which can lead to sooty mold. Spraying the leaves with a forceful stream of water, such as from a hose, will help wash the aphids off. Ophryocystis elektroscirrha a monarch parasite can occur on this plant in locations where this plant does not die back in the winter months. This protozoan parasite can be left on the leaves of a plant by visiting monarchs. As the caterpillars eat the leaves, they also ingest the parasite. This can lead to a shortened lifespan, lower body mass and their flight ability. Cutting the plant down will help to remediate this issue but the best course of action is to plant one of the native milkweed (found in the left hand column) instead.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Fills a similar nicheAsclepias quadrifoliaLantana camara 'Ham and Eggs'Lantana camara 'Miss Huff'
Full sun (6 or more hours of direct sunlight a day)
Soil texture
High Organic Matter; Loam (Silt); Sand
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage
Available space
12 inches-3 feet
NC region
Coastal
Mature size
Height: 2 ft. 0 in. - 3 ft. 0 in. | Width: 1 ft. 0 in. - 2 ft. 0 in.
Growth rate
Medium
Maintenance
Low
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Erect
Texture
Medium
Foliage
Deciduous
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate; Opposite; Whorled
Leaf shape
Lanceolate
Leaf margin
Entire
Leaf size
3-6 inches long, 1-3 inches wide
Hairs present
No
Leaf detail
The narrow leaves are simple, alternate, opposite, or whorled. The medium green leaves may have a white midrib.
Flower color
Gold/Yellow; Orange; Red/Burgundy
Flower value
Long Bloom Season; Showy
Flower form
Cyme
Flower size
< 1 inch
Flower detail
Brilliant orange-red with yellow flowers in clusters spanning 2-4" across. Each cluster can contain 6 to 15 flowers.
Bloom time
Fall; Summer
Fruit color
Brown/Copper
Fruit type
Follicle
Fruit value
Showy
Fruit size
> 3 inches long, < 1 inch wide
Fruit detail
The fruits are dry and inflated with an erect follicle and many hair-tufted seeds. They are often used in dried arrangements.
Stem detail
The stems can be simple or branched.
Wildlife & Ecology
Native status
Non-native
Origin
Mexico to Tropical America
Wildlife value
Attracts hummingbirds, butterflies, bees, and moths. Although monarch butterflies are attracted to this plant, the butterflies are better served by native species. See text.
Can cause stomach upset, nausea, vomiting, abdominal pain, diarrhea, weakness, lethargy, and confusion if eaten in quantity. Milky sap can cause contact dermatitis and eye irritation