STUDY: Planting Milkweed Mixed With Other Wildflowers is Best Strategy for Saving Monarch Butterflies

March 1, 2021 at 5:10 pm

Monarchs lay more eggs in mixed wildflowers than milkweed-only gardens, new research shows.

97% of monarch butterflies have disappeared in just two decades. In a race to save them from extinction, experts are scrambling to determine what we can do to help them.

So far, planting urban milkweed gardens has been the number one strategy.

Until now, scientists have recommended we plant milkweed-only gardens, so butterflies didn’t have to sort through a variety of flowers to find their food of choice.

But a new study suggests a diversity of native wildflowers actually yields better results than a mono-culture of milkweed.

Researchers from the University of Florida hypothesized that milkweed-only gardens would attract and support larger populations of monarchs.

They assumed an isolated, bright patch of milkweed would be more visible to the butterflies and feared that planting a diversity of flowers would attract more monarch predators.

They were wrong.

Not only did monarchs lay 22% more eggs on milkweed stems in diverse flower gardens, predators and parasites did not increase.

For the study, the researchers compared mono-crop gardens of swamp milkweed to mixed patches planted with swamp milkweed, aquatic milkweed, dense blazing star, swamp sunflower and scarlet rosemallow.

“Contrary to our prediction, we demonstrate that swamp milkweed plantings surrounded by other native wildflower species are colonized by monarchs more than swamp milkweed plantings surrounded by other swamp milkweed,” entomologist and lead study author Rebecca Nestle writes.

“We also found that increasing floral richness had no effect on monarch predation or parasitism.”

“This suggests that creating diverse monarch conservation plantings, particularly in urban garden settings, may benefit both monarchs and other beneficial insects.”