Once spring arrives, gardeners will head to their garden center to buy beautiful flowering plants. If you’re in zone 7 or colder, go ahead and reach for that beautiful tropical milkweed!
As you have learned from earlier writings, milkweed, Asclepias species, is the only plant for the monarch butterfly (Danaus plexippus) to lay her eggs. I’m sure you’ve heard a lot lately about our non-native milkweed, the tropical milkweed, Asclepias curassavica, considered bad for the fall migrating monarchs. There are seventy native milkweed series to the US and Canada. So why do we need even to bother planting a non-native variety? Well, in my #BeeBetter garden, it’s because the monarchs seem to prefer it. Click to Tweet!
The Bee Better Teaching Garden grows around ten varieties of Asclepias. We like the variety of colors and textures. We even have a wild native that comes back year-to-year. Do the monarchs like it? Well, I’m not sure. I’ve never seen a single monarch, at any stage of life, on any species except the tropical milkweed, Asclepias curassavica. So that’s good, right?
More and more information finds the tropical milkweed that winters-over could cause harm to the monarch by delaying migration In doing so, according to a study from UGA, the evergreen nature of tropical milkweed may increase the rate at which monarchs are infected by the parasite Ophryocystis elektroscirrha (OE). This information revealed the longer the monarch caterpillar remains a resident, the higher number of OE parasites found.
So what does this mean to you? If you live in a zone 7 or higher, tropical milkweed isn’t evergreen for you. If you live in a more temperate zone, 8 and higher where the tropical milkweed is an evergreen perennial, you may want to cut the plant to the ground by the time of your first frost.
THE NOT SO UGLY!
How can something so bad in warmer climates be so pretty? Well, it just is. This is why nurseries are more likely to carry the tropical milkweed than any other. People like to buy pretty blooms. If you are in zone 7 or higher, buy on. It will die back and you will not be contributing to the problem often being addressed.
In the Bee Better Teaching Garden, we had several native milkweeds last loner from a frost than the tropical milkweed. We’d like to see the same study on the native Asclepias!