Planting milkweed for Monarchs is one of the important first steps in starting a butterfly garden this spring.
Once you have decided to plant milkweed, the next step is to choose which type of milkweed will be best for your site. Monarch Joint Venture has a brochure that details the milkweed species that are native to the central United States. Some of the milkweed species in the brochure can be hard to find in local nurseries but are worth searching for.
If you have not already started your own native milkweed plants from seed, the milkweed variety that you plant this year will depend on what is available at plant nurseries. While there are about 100 species of milkweed native to the United States, very few are commercially available. Swamp Milkweed is often found for sale, as is Butterfly Milkweed.
In many parts of the United States, Tropical Milkweed is the milkweed most commonly found for sale. Not native to the United States, it is an attractive plant with bright red or yellow flowers. It is easy to grow from seed and is the always the first milkweed in my garden to have Monarch caterpillars happily munching away on its leaves. If started from seed in spring, it could be late summer before flowers arrive but in the meantime it will be a source of tender milkweed leaves that are very attractive to egg laying Monarchs. Many years, my stand of tropical milkweed has very few flowers because the plants are eaten down to the stalk by hungry Monarch caterpillars.
Many butterfly gardeners feel that Tropical Milkweed is a problematic milkweed due to the Monarch parasite Ophryocystis elektroscirrha (OE). The parasite is transferred as a spore, moving from milkweed to milkweed attached to the adult Monarch’s abdomen. The buildup of this parasite in Monarchs can limit their life span over time. In parts of the southern United States where Tropical Milkweed is grown as a perennial, to avoid a buildup of OE spores it is suggested that Tropical Milkweed be grown as an annual (by removing plants each year), cut back to the ground once or twice a year, or not grown at all.
Find more about milkweeds on nababutterfly.com’s Monarchs and Milkweed page.