A few decades ago, milkweeds (genus Asclepias) were simply common native plants that could be poisonous to livestock, so they were ignored or eliminated. Then monarch butterfly (Danaus plexippus) populations were found to have decreased dramatically. Looking for causes, ecologists pointed to land development eliminating milkweeds, which are the only food plant of monarch caterpillars. Trying to help, people all over have been planting milkweeds for the monarchs.
 |
Showy milkweed, Asclepias speciosa with a monarch butterfly perched on it |
For people living in Eastern North America, common milkweed (
Asclepias syriaca) was the easiest milkweed to find and grow and it is a monarch magnet. In the West, though, common milkweed is not native. It is replaced by showy milkweed (
Asclepias speciosa), which grows in many of the same habitats and looks quite similar. Over the last decade, western nurseries and gardeners have explained this and made showy milkweed seeds and plants available. Today you can google all kinds of information about showy milkweed (
link,
link,
link and many more). What can I possibly write? I will draw some aspects of the wild plants to your attention.