The counts are in, and monarch butterflies are doing a bit better this year, though there is still much to be done. Gardeners can help in many ways—primarily by planting native species of milkweed.

In recent years, butterfly aficionados and nature lovers have watched in horror as the population of monarch butterflies has crashed. The fight to save them is turning out to be more complicated—and more contentious—than many expected.

There is some good news, though: The population of monarchs that spent the winter in their usual forested haunts in Mexico increased a bit in 2015 from the record low populations in 2014, according to National Public Radio.

During the winter season, the total Mexican forest area occupied by monarch colonies was 1.13 hectares, up from the record low of 0.67 hectares last year. NPR reports that it’s unclear why there was a modest improvement in monarch populations this year, but better weather conditions in Mexico than last year probably played a role. Still, the number of monarch butterflies is frankly pathetic.  NPR says nearly a billion monarch butterflies fluttered about a quarter century ago. Now, that number is closer to 30 million — that’s a a 97 percent drop!

Clearly, the monarch population is still in big trouble.

Scientists point to a number of possible causes. Monarch habitat is disappearing, carved up by new housing developments, strip malls, parking lots and roads.

Herbicides, especially glyphosate-based formulas like Monsanto’s Roundup, are even bigger suspects. Farmers and homeowners have been spraying more and more of the stuff on their fields and lawns, killing weeds and protecting crops, but also decimating milkweed, a once-common “weed” upon which monarchs depend to survive.

Plant milkweed, but make it local

Gardeners, experts and nature lovers have concluded that by planting more milkweed—the sole food source for the monarch caterpillar—we might be able to help our orange and black friends.

As with many things in nature, it’s not that simple.

It’s true that many gardeners who’ve planted milkweed are helping, but it’s especially important to plant the right milkweed species. According to a Science magazine report, well-meaning gardeners have been planting tropical milkweed, Asclepias curassavica. The problem is that, when planted in southern locations such as south Texas or the Gulf Coast, tropical milkweed doesn’t die back in the winter like other milkweed species. This can confuse monarchs into foregoing the rest of their migration. In addition, tropical milkweed plants can sometimes host a parasite that harms monarchs, infecting successive generations of butterflies.

Avoid planting tropical milkweed and instead look for these species: Asclepias syriaca, Asclepias incarnata, Asclepias speciosa, Asclepias sullivantii. If your garden center doesn’t carry these, ask them to stock these native varieties—or order by mail.

Lawsuit targets glyphosate

In February, the environmental group Natural Resources Defense Council filed suit against the federal Environmental Protection Agency, saying the department failed to heed warnings about the risks glyphosate poses to monarchs, Reuters reports. The lawsuit is still pending.

Under fire with accusations that its product plays a role in monarch declines, Monsanto declared in March that it is donating $4 million to help save the monarch habitat. Recipients include national and regional organizations and universities that are studying and combating the butterfly population crisis.

More resources

  • Monarch Watch: a non-profit clearinghouse of information and resources dedicated to helping save the monarchs. Monarch Watch also has an online store where you can buy butterfly nectar and monarch waystation seed kits for your garden.
  • Saving the Monarch Butterfly: In this article, you can learn more about what gardeners can do to help.
  • Create a Monarch Waystation: Monarchs are in trouble at least in part because of the elimination of milkweed that used to grow in farm fields. Grow a patch of milkweed in your backyard to provide food for monarch caterpillars.
  • Planters and Raised Beds for Butterflies: To attract butterflies and other pollinators, simply plant flowers they love—lots of them. The designs here feature blooms that are rich in color and nectar, ensuring that you will welcome dozens of beneficial insects—especially butterflies.
Matt Sutkoski

Matt is a Gardener’s Supply employee, avid gardener, journalist and weather geek who lives amid an acre of perennial beds and vegetable plots in St. Albans, VT.