There’s not a one-size-fits-all monarch garden. Although the Field Museum’s project is still fairly new, there are already some findings after a pilot and pandemic season. Participants sent in weekly reports, including the makeup of their garden, and development of eggs and caterpillars.
The most prevalent kind of milkweed planted among project participants was common milkweed, and it was associated with the most eggs. And while participants planted close to the same amount of swamp and butterfly milkweed, they reported about four times as many eggs on swamp milkweed.
The more successful gardens had more milkweed and blooming plants multiple milkweed species, and they tended to be larger plots. But there were small victories.
Klinger said one participant with a single plant watched eggs transform all the way to a chrysalis. So, she said, “You just need one plant.”
But now is the perfect time to start planning to plant some milkweed, Hasle and Klinger said. They recommend checking out native plant sales and preordering; milkweed can be in high demand come June.