Tropical Milkweed - Asclepias curassavica
Other common names for this plant include Scarlet Milkweed, Mexican Milkweed, Bloodflower, and Silkweed.
Technically not native to the United States, tropical milkweed is widely popular in butterfly gardens. 
Growing as a naturalized perennial plant in the southern U.S., it can also be easily started from seeds in the northern U.S. and treated as an annual. For an even longer blooming period in colder regions, tropical milkweed plants are easily potted up in the fall and grown indoors over the winter.
Blooming over a wide range of months (depending on location), many sources claim that tropical milkweed is the preferred milkweed for monarch caterpillars due to its tender leaves. Whether or not this is true, it is certain that tropical milkweed is a popular as both a caterpillar food plant and butterfly nectar plant.
The one problem that plagues the appearance of tropical milkweed in the garden are aphids. Lots and lots of aphids. Aphid control on outdoor plants may be as simple as spraying the plants with a burst of water from the hose which will dislodge the aphids (and which will have to be repeated all season). Generally, aphid infestations are a bit unsightly but do not impair blooming or plant growth.
A second problem that can impact the appearance of tropical milkweed is a result of the severe defoliation caused by Monarch and/or Queen caterpillars. This problem of course has the trade off of providing great caterpillar watching while helping to produce more butterflies. Once the plants are defoliated or the caterpillars have moved on, it is a simple matter of cutting back the tropical milkweed, which will resprout from the plant's base. Regrowth is fairly fast and the plant will rebloom.
Importance as a caterpillar food source: Like many milkweeds, tropical milkweed is a food plant for Monarch caterpillars. Queen caterpillars, which are found in the southern states, particularly Florida, southern costal areas, Texas, and the southwest, will use tropical milkweed as a food source. Additionally Soldier caterpillars, which are locally common to southern Florida and Texas, can be found on tropical milkweed.
Importance as a butterfly nectar source:
In addition to Monarchs, tropical milkweed provides nectar for a wide variety of butterflies, pollinators, and hummingbirds.
| USDA Hardiness Zone | 8B - 11, remains evergreen in 9B - 11, can be grown as annual in zones north of 8B |
| Bloom Period | Continual bloom spring thru fall |
| Bloom Color | Scarlet red, orange or yellow |
| Plant Height | 36 to 48 inches |
| Plant Spread | varies with age of plant |
| Light Exposure | Sun to part shade |
| Soil Moisture | Moist to average to dry |
| Animal/Pest Problems | Deer resistant, aphids may be a problem |
Native Range for Tropical Milkweed- Asclepias curassavica
This plant has been rated in the following locations: Pinellas Co., FL:This plant is a wonderful addition to any butterfly garden! I have a minimum of ten butterflies flying around this milkweed every morning. Sow seeds directly in the ground after the cold snap FL usually gets in Jan./ Feb. Aphids can be a problem. Palm City and Naples FL also rate tropical milkweed as a 'must have.' Schuylkill Haven, PA: Monarchs LOVE this plant and laid lots of eggs on it! Los Alamitos, Orange Co., CA: I started off with one plant... I had never seen a Monarch in my area..now Monarchs and their caterpillars are everywhere in my yard (I now have five plants.) Portland, San Patricio, TX: I had many Monarchs and Queens this year and they loved this variety of milkweed. Johnson & Miami Co., KS: Tropical milkweed is an annual in this area. Most seeds left out over the winter months do not survive and therefore it does not self-seed. |