If We Want to Save Monarchs, We’re Going to Need A Lot More Milkweed

As recently as the 1990s an estimated one billion monarchs made their way from the U.S. and Canada to the oyamel fir forests in Mexico, where they spend winter sheltered by the trees before returning North. Sadly, they’ve declined at an alarming rate and now, according to a new study, it’s going to take more than one billion milkweed stems to help bring these iconic butterflies back from the brink.

Monarchs, who have declined by more than 80 percent over the past two decades, are currently being considered for protection under the Endangered Species Act, but a final decision isn’t expected until June 2019. In the meantime, their advocates have been working on measures that could help them survive, including increased calls for planting milkweed.

Monarchs face a number of threats and challenges along their epic migration, but one of the biggest threats they face today is a loss of milkweed. It’s the only plant that monarchs lay eggs on and the only plant monarch caterpillars will eat.

Other threats to monarchs range from predators and disease to habitat loss, pesticide use and severe weather.

Monarch caterpillar on milkweed plantCredit: Thinkstock

According to a study just published in Environmental Research Letters, it’s going to take more than 1.6 billion additional milkweed stems in North America to help restore eastern migratory monarchs to a sustainable population size.

For the study, researchers developed different scenarios to see where milkweed would be most effective, including protected lands, Conservation Reserve Program lands, utility and transportation rights-of-way land and agricultural lands, in addition to urban and suburban areas.

According to the USGS, if at least half of marginal agricultural land in the Midwest is converted to monarch-friendly habitat, it could bring a full population recovery, but efforts that expand on that would be far more effective.

“The main finding of our study is that an all-hands on deck approach could be essential to restoring the massive amounts of milkweeds needed to make the monarch population healthy again,” said Wayne Thogmartin, a USGS scientist and the lead author of the study. “These findings offer great hope for citizens from all sectors working together to reverse the substantial decline of these iconic butterflies.”

Ultimately, the U.S., Mexico and Canada are aiming to meet a tri-national goal of increasing the number of monarchs wintering in Mexico to a point that they cover about six hectares, or roughly 15 acres of land, by 2020, which is about double what they covered over this past winter.

“Encouraging urban and suburban areas to participate along with the agricultural sector could create a crucial spark of public support and momentum for monarch conservation across the board,” said Laura López-Hoffman, a conservation biologist at the University of Arizona who co-authored the study.

Organizations including Monarch Watch and the Xerces Society for Invertebrate Conservation have resources for people who want to help by planting milkweed, but people are also being encouraged to plant other native flowering plants to help feed them, and other pollinators, throughout the year.

For more on how to help, check out the Xerces Society, Monarch Watch, USGS Monarch Conservation Science Partnership, Monarch Joint Venture and Save the Monarch.

Photo credit: Thinkstock


Marie W
Marie W11 months ago

thank you for sharing

Amanda M
Amanda Mabout a year ago

This year, I saw that the county maintenance workers are actually mowing AROUND the milkweed patches when they mow the roadsides! Not only that, but several booths at our town's Green Fest were giving away milkweed seed packets for people to plant it in their own yards. My parents already have milkweed growing in their front flower beds and have enjoyed monarchs coming back every year, and I've got a volunteer patch of it growing in my vegetable garden that my husband has strict orders not to till up! Every little bit helps.

Cindy M. D
Cindy M. Dabout a year ago

Monarchs are so beautiful. We must all do what we can to fix what we broke.

Sue R
Sue Rexabout a year ago

It takes little effort on our part to plant a few milkweed or other butterfly friendly plants in our yards or balconies. Wildlife need all the help they can get from us because of what we are doing on this planet, so we should all chip in and help.

Michele B
Michele Babout a year ago

one of the most colorful and beautiful of God's creations now needing OUR help to save them BECAUSE of our carelessness

Camilla Vaga
Camilla Vagaabout a year ago


Carl R
Carl Rabout a year ago


Christine Stewart
Christine Stewartabout a year ago

It would be so easy to plant this around schools, dog parks, etc- as a green belt that helps butterflies!

Panchali Yapa
Panchali Yapa Yapaabout a year ago

Thank you

Carl R
Carl Rabout a year ago