Gardening Flowers Annuals How to Plant and Grow Tropical Milkweed Grow this a annual milkweed with showy red and orange flowers as a host and nectar plant for the monarch butterfly. By Nadia Hassani Nadia Hassani Nadia Hassani is a gardening and food writer with more than two decades of hands-on gardening experience in vegetable and fruit gardening, landscaping with native plants, and garden design. Learn about BHG's Editorial Process Updated on June 12, 2023 In This Article View All In This Article Where to Plant Planting Tips Care Pests and Problems Propagation Types Companion Plants FAQ Trending Videos Close this video player Like other members of the milkweed genus, tropical milkweed is one of the best plants to attract butterflies, bees, and other beneficial insects, as well as hummingbirds. Tropical milkweed is a host and nectar plant for monarch butterflies, whose larvae feed on the leaves. It is a relatively drought-tolerant plant and perfect for planting in sunny naturalistic or wildlife gardens. In midsummer—in southern climates already starting in the spring—it covers itself with gorgeous flowers in oranges, reds, and yellows on tall stems. Although the plant is a perennial in tropical climates and keeps growing all through the fall and winter, it should be grown as an annual to prevent monarchs from feeding at the wrong time of the year and foregoing their natural migration (see more under Pruning below). Milkweed is toxic to humans and pets. Tropical Milkweed Overview Genus Name Asclepias curassavica Common Name Tropical Milkweed Additional Common Names Bloodflower Plant Type Annual Light Sun Height 3 to 4 feet Width 1 to 3 feet Flower Color Orange, Red Foliage Color Chartreuse/Gold Season Features Fall Bloom, Summer Bloom Special Features Attracts Birds, Cut Flowers, Good for Containers, Low Maintenance Zones 10, 11 Propagation Seed Problem Solvers Deer Resistant, Drought Tolerant Where to Plant Tropical Milkweed Full sun is the most important criterion when selecting a location for tropical milkweed. Soil quality is secondary, as tropical milkweed can grow in any type of soil that is slightly acidic, neutral, or alkaline. Wherever you plant tropical milkweed—in a border, cottage garden, butterfly garden, or meadow—make sure that it sticks out from the foliage and flowers of other plants, which helps attract monarch butterflies. How and When to Plant Tropical Milkweed Plant it in spring after all danger of frost has passed. Tropical milkweed has a taproot and the younger the plant, the better it will tolerate transplanting. Dig a hole about twice the diameter of the nursery pot and about the same depth. Place the plant in the hole and fill in original soil to the top of the root ball. Gently tamp down the soil and water it well. Keep it watered for at least one week, or until the plant has visibly grown. Space plants 2 to 3 feet apart. Tropical Milkweed Care Tips Light Tropical milkweed needs full sun for at least 6 hours every day. Soil and Water The plant is not finicky about the soil in which it’s grown—it can grow in dry as well as in moist or moderately wet soil and over a wide pH range (6.0 to 8.0). Once it is established, it can tolerate dry conditions but does better with consistent moisture. Temperature and Humidity As the name says, it is a tropical plant that won’t survive frost. It does not have any specific humidity needs or dislikes. Fertilizer Tropical milkweed does not need fertilizer. It can even grow in nutrient-poor soils. Pruning Pinching the young plants to encourage branching with more flower clusters is optional. What is not optional, however, is cutting down the plants to the ground in the fall if they don’t die on their own from the frost. Because if the plant remains alive, monarch butterflies will continue to feed on it instead of migrating south, a disruption of the natural cycle that is fatal for this endangered butterfly species. Potting and Repotting Tropical Milkweed Tropical milkweed adapts well to container-growing, as long as you plant it in a tall 1-gallon container to fit its taproot. Choose a container with large drainage holes and fill it with well-draining potting mix. Keep in mind that container plants require more frequent watering and fertilization than plants in the landscape. Repotting of annual tropical milkweed won’t be necessary. Even if your winters are mild and the plant remains green, don’t leave it outdoors. Either cut it back to the base or bring it inside for the winter where monarch butterflies cannot feed on it. Pests and Problems Serious pest infestations of tropical milkweed are uncommon, but you might find aphids on the plants, which can cause sooty mold fungus from the aphid secretions. In the mid to late summer, you might also find orange and black milkweed bugs on the plants. Tropical milkweed is deer-resistant. How to Propagate Tropical Milkweed Tropical milkweed is best propagated from seed. Because it can take tropical milkweed about four months to start blooming, start the seeds indoors 8 to 10 weeks before the last frost date in your area. Soaking the hard seeds in water for 24 hours before planting improves germination. Plant the seeds about 1/4 inch deep in potting mix and keep them evenly moist. Germination takes place in 2 to 3 weeks. Unless you start them in a greenhouse with plenty of natural light, you will need grow lights to prevent the seedlings from becoming leggy. Harden the young plants off before transplanting them outside after the last spring frost. Types of Tropical Milkweed Silky Gold Tropical Milkweed Asclepias curassavica 'Silky Gold' has large clusters of golden yellow flowers and yellow-green foliage. It reaches 3 to 4 feet in height and 2 to 3 feet in width. Silky Deep Red Tropical Milkweed The deep red flowers of Asclepias curassavica ‘Silky Deep Red’ have tips that are bright yellow. It grows 3 to 4 feet tall and 2 to 3 feet wide. Red Butterflies Tropical Milkweed Asclepias curassavica 'Red Butterflies' has clusters of scarlet-red and yellow flowers. It is slightly smaller than the other cultivars, growing 3 feet tall and 2 feet wide. Companion Plants for Tropical Milkweed Milkweed Combine tropical milkweed with perennial milkweeds that are native to your area, such as common milkweed with deep pink flowers or butterfly weed with fiery orange flowers. Zones 3-9 Aster Easy-to-grow asters come in a variety of shapes and sizes to suit gardens of all dimensions, shapes, and styles. As a companion plant for tropical milkweed, pick shorter, or compact asters so they don’t tower over the milkweed. Zone 3-9 Blazing Star Blazing star flowers are a favorite nectar source for butterflies like monarchs and many other pollinators. After the bloom, the seeds make a nutritious snack for finches and other small birds. Zone 3-9 Frequently Asked Questions Is tropical milkweed invasive? Tropical milkweed prolifically reseeds itself if the seed pods remain on the plant—to the point that it has become invasive in some areas of the southeastern United States. In view of the detrimental effects that perennial tropical milkweed can have on monarch butterflies and the potential of the plant developing into monocultures, it is much better to plant milkweed varieties that are native to your area. Can I overwinter tropical milkweed? You can overwinter potted milkweed by bringing it indoors for the winter. In fact, even if your climate is mild enough for the plant to survive the winter, moving it out of the reach of monarch butterflies is the right thing to do. Treat it like a houseplant that needs bright light. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit Sources Better Homes & Gardens is committed to using high-quality, reputable sources—including peer-reviewed studies—to support the facts in our articles. Read about our editorial policies and standards to learn more about how we fact check our content for accuracy. Milkweed Plant Can Cause Serious Poisoning. National Capital Poison Center. Milkweed. ASPCA. "Asclepias curassavica." University of Florida Extension.