Let’s get one thing straight, it’s not you, it’s me. Ok, what I really mean is it’s your tropical milkweed. We get asked frequently about how people can get involved with saving the monarch butterflies. Our best advice for you is to safely watch your backyard pets but avoid interfering with their life cycle. It may be difficult, but it’s what is best for the species. There are two main reasons why you should try to avoid tropical milkweed in your garden. First, there is a microscopic parasite called Ophryocystis elektroscirrha or OE that can accumulate on tropical milkweed and around the environment as spores. When a caterpillar consumes the milkweed, the spores are also ingested. Once inside the body, they are able to multiply. When the caterpillar pupates and ecloses as an adult butterfly, the wings can be crippled and the adult will not be able to fly. Unfortunately, this causes the butterfly to starve as it cannot nectar or pollinate plants. When a healthy butterfly nectars from a milkweed infested with OE, it can transfer the spores to more individual plants.
The second issue with tropical milkweed is that is discourages the monarchs from migrating. We would like to mention that this issue mainly occurs in areas where tropical milkweed grows year round without dying back, like South Florida. With the host plant available all year, the females will continue to lay eggs locally instead of flying towards their migration pattern to find more.
What can you do? Shop at local nurseries for native milkweeds. There are 20 species of milkweeds that are native to Florida. For the South Florida area, we suggest searching for butterflyweed (Asclepias tuberosa), swamp milkweed (Asclepias incarnata), whorled milkweed (Asclepias vericillata), and green antelopehorn (Asclepias viridis). While it may be difficult to find these, it should be your first purchase instead of tropical milkweed. If you absolutely can’t find native milkweeds, you can try tropical milkweed but there is one rule you must live by; you must cut your plants back after Halloween. Why, you might ask? Cutting the tropical milkweed not only eliminates the spores of the OE but it also helps encourage the monarchs to follow their migration pattern.
