What are the potential problems associated with planting tropical milkweeds?

Research by Satterfield et al., 2015, shows very clearly that monarchs breeding on tropical milkweed throughout the winter have higher levels of protozoan infection (caused by Ophryocystis elektroscirrha, OE) compared to monarchs in the migratory cycle. Please see the Monarch Joint Venture Fact Sheet and our Q&A with monarch and tropical milkweed experts for more information about the potential risks of growing exotic milkweed for monarchs.