Feb. 2, 2018

tropical milkweed, Asclepias curassavica

Tropical milkweed is much planted for butterfly food. Monarch's like it as much as they do our native milkweeds. It is a subshrub, with stems that will persist for many seasons if it's warm enough. And there's the rub. This species is a host for parasites that decrease survival of the butterflies. Research has shown that the older stems are the source of the problem, building up too many parasite spores as they age. If tropical milkweed plantings are cut back a couple times each year, the parasites can be kept to natural levels. Tropical milkweed is now naturalized in AL, CA, FL, HI, LA, TN, TX, and around the world in the tropics. Hillsborough Co FL, 1/23/13.