While efforts taking place across the country to plant milkweed and help the monarchs is a wonderful cause, it is extremely important to make sure you’re not planting the wrong species of milkweed.
Which milkweed species to plant: there are over a hundred different species of native milkweeds in North America (species in the genus Asclepias), and all are great for monarch butterflies. If you are not sure which type of milkweed is best suited for your area, ask your garden or nursery retailer for help. You can also reference this guide from the Xerces Society.
Which milkweed species to avoid: tropical milkweed (Asclepias curassavica – also called blood flower or scarlet milkweed)
Tropical milkweed stays green and succulent longer during the growing season than native North American milkweeds, increasing the risk of disease-related death for monarchs, and interfering with their migration. If you live in the southern U.S. and you’ve already planted tropical milkweed, make sure to cut it down or bring it in during the monarch’s fall migration. If you live in the northern U.S., tropical milkweed should die on its own after frost.
Remember – it is also important to ensure you are not planting milkweed and other pollinator-friendly flowers that have been pre-treated with pesticides, which can harm monarch butterflies and other pollinators visiting the plants. Most insecticide-treated plants are not labeled as such, so you may need to ask your garden or nursery center to confirm that the plants are not pre-treated and harmful to the very species you’re trying to help out.