Want monarch butterflies? Plant milkweed this fall

If you think there are fewer monarch butterflies fluttering about, you’re right.

Because of a loss of milkweed, there’s been an 80 percent decline of monarch butterflies in the last 20 years, said Eric Topper, director of education for Maine Audubon.

And there’s something Mainers can do about it right in their own yards: Plant milkweed. “We need milkweed anywhere we can plant it,” Topper said.

Milkweed is critical. While adult monarch butterflies consume nectar from various flowers, milkweed is the only plant on which adult monarchs lay their eggs because it is the only plant monarch caterpillars eat.

The fall — October and November — is the best time to plant milkweed seeds to attract beautiful, orange monarchs to your yard, Topper said.

Three varieties of milkweed grow well in Maine: common milkweed, butterfly milkweed and swamp (or rose) milkweed.

Topper cautioned against planting common milkweed, which is native but takes over any area where planted. “I own a one-quarter acre and planted common milkweed years ago. They run over everybody else. I will be pulling them out of my yard the rest of my life,” he mused.

Gardeners will enjoy adding swamp milkweed, which has pink flowers, or butterfly milkweed, which has orange flowers. Both behave better in that they don’t take over other plants and are just as beneficial to monarchs, Topper said.

Milkweed seeds are available from the Wild Seed Project in Portland and Native Haunts in Alfred. Prairie Dawn is another good national source, but be sure the plants are native to Maine, Topper said.

While most planting is considered a spring activity, milkweed seeds need to be planted in the fall. “They need to stay outside all winter,” Topper said. “They need to freeze and thaw, freeze and thaw. To germinate they need that cold. This is the perfect time for people to buy seeds and sew those seeds.”

Monarchs are unique for their annual migration from Maine to Mexico, flying in packs. Because of their long migration, “they are a continental species. They go through every major city. They are so familiar to so many,” said Topper.

MAINE’S ROLE IN THE MONARCH CYCLE

Maine plays an important role in the annual migratory cycle of the monarchs, Topper said, because the state is the northern terminus for many monarchs, which have a fascinating cycle stretching from Mexico to Maine and similar northern regions.

In the fall, monarchs recently born in the north will migrate in groups up to 3,000 miles to central Mexico, where they will hibernate, huddling by the millions in Oyamel fir trees.

In the spring, those same monarchs will wake up, mate, lay eggs and die, having lived seven to eight months. Within six weeks or so, their offspring will have gone through the four stages of their lives from egg to butterfly — feasting only on milkweed as larvae — and turn into butterflies.

Those young monarchs will head hundreds of miles north to places like Texas and other southern states, where they will mate, lay eggs and die within five to seven weeks.

Another generation will be born and turn into butterflies — again, the larvae will eat only milkweed — and move a little farther north to mate, lay eggs and then die.

In all, four to five generations are born throughout spring, summer and into the early fall. When they start arriving in Maine, Canada and other northern regions in mid-August on their final journey north, that generation will again mate, lay eggs on milkweed plants and die.

But their offspring will be special. “This generation has extra responsibilities,” Topper said. This super generation has the genetic makeup to migrate all the way to Mexico and will have a longer lifespan of six to eight months, starting the cycle all over again.

“The peak abundance range to see monarchs in Maine is mid-August (when monarchs arrive from the south) to mid-October (when their hearty offspring leave Maine for Mexico),” Topper said.

The main threat to monarchs is the loss of milkweed, especially in the Midwest, Topper said.

Fields that used to be covered with milkweed have been converted to corn and soy, he explained. Special corn and soy varieties have been developed that are resistant to a specific, controversial herbicide called Roundup.

“Many call it ‘Roundup-ready corn,'” Topper said. “It’s been genetically engineered so if you spray it with poison (Roundup), everything else but the corn and soy will die. They don’t have to pull milkweed by hand. They do it by planes.”

With less milkweed in the Midwest, “monarchs can’t reproduce. This is where the real problem is,” he said. “We’re not getting the monarchs in Maine largely because of the habitat loss in the Midwest.”

The good news is that many people — from students to citizen scientists to gardeners — are planting milkweed “to make sure the monarchs who get here have a chance,” Topper said.

Restoring monarchs is infectious, he said, “because it actually works. So many people buy milkweed from us,” plant it and see monarchs the next year. They call to excitedly report: “Oh my gosh it works!” Topper said.

Typically it takes a full growing year for new milkweed plants to establish and produce flowers, but the plants can start hosting monarchs in the first season, even when plants are small, Topper said. As long as there are leaves, monarchs may lay eggs.

While their population has been dramatically reduced, monarchs aren’t likely to go extinct, Topper said, because they’re easy to raise in classrooms and yards.

“We can probably keep monarchs on Earth,” Topper said. “At risk is the historic migration phenomenon.”

bwashuk@sunjournal.com

Monarch butterflies are in decline due to a loss of habitat. Mainers can help by planting milkweed, a plant crucial to its reproduction. The monarch in this photo is on a swamp milkweed flower. (Eric Topper/Maine Audubon photo)

A monarch caterpillar on a milkweed leaf at Maine Audubon in Falmouth. Monarch caterpillars will only eat milkweed. This caterpillar will soon become a butterfly and migrate with other monarchs to Mexico. (Bonnie Washuk photo)

Topper speaking in Auburn next month

AUBURN — On Oct. 3 at noon, at the Auburn Public Library, Eric Topper, Maine Audubon’s director of education, will present a discussion exploring the plants, practices and perks involved in restoring native food webs in our gardens, yards and communities.

The talk is part of “Bringing Nature Home,” Maine Audubon’s new community engagement and habitat stewardship initiative based on the bestselling book of that title by Doug Tallamy.

The talk, which will be held in the library’s conference room, is co-sponsored by the library and the Stanton Bird Club in recognition of “The Year of the Bird,” an international celebration of birds.

Common milkweed, which is native to Maine and the type of milkweed often found here, is very hearty and tends to take over an area, so experts recommend planting swamp milkweed or butterfly milkweed instead. (Courtesy of the Wild Seed Project)

Eric Topper, director of Education at Maine Audubon, says more milkweed plants would help the monarch butterflies who fly to Maine from the Midwest. Topper is shown surrounded by milkweed at Maine Audubon in Falmouth last week. (Bonnie Washuk photo)

An illustration in the children’s book “A Monarch Butterfly Story” by Melissa Kim and Jada Fitch, shows how monarchs move north from Mexico each spring, and over successive generations born throughout the summer find their way to Maine and other northern regions. The last generation of monarchs born in the late summer and fall each year then migrate to Mexico for the winter. The book is available at Maine Audubon. (Islandport Press photo)