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Signs of the Seasons: A New England Phenology Program

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Maintaining a Milkweed Patch

For those with milkweed in their yards, the color and scent of the flowers adds to the landscape and may even attract monarch butterflies. But, what happens after the blooms have faded? What is the best way to maintain a patch of milkweed for both landscaping and the monarchs?

Lois Stack, Horticulture Specialist and Signs of the Seasons adviser, offers some guidelines:

There are three approaches to managing a colony of milkweed. First, the milkweed can be left on its own. If there’s enough space, this is a great method because the seed heads break open and the seeds can spread in the wind. This enhances the likelihood of milkweed establishing in a new site from one of the seeds.

The second method, if the seeds are not wanted, is to remove the seed heads before they mature. Monarch larvae do not feed on the seed heads, so removing them does not threaten the insects.

Finally, if mowing is necessary, milkweed can be cut down very late in the season, after all butterfly larvae have metamorphosed from pupae into adults. If some of those pupae (called chrysalises) are still hanging on the plants, allow more time for them to mature and develop into adults. If there are no chrysalises hanging on the plants, then the plants can be mowed. Wait as long as possible before mowing. The safest timing is following a hard frost. However, if that is not possible, check for pupae in late September and decide about mowing.

Volunteer in the Spotlight

Dr. Orrin Shane’s lifelong interest in milkweed began when he was a boy in the 1940s. He and his childhood friends picked bushels of the plants for the war effort. The fluffy insides of pods were used to fill life preservers for soldiers overseas. “That was my introduction to milkweed,” Shane said. “It is a plant of many faces.” Today, as a volunteer of the Signs of the Seasons phenology program, Shane regularly observes milkweed for signs of Monarch butterflies and caterpillars. He found his current stand accidentally after a futile search of his Portland neighborhood. Read more.

Image Description: Orrin Shane

The Story of Milkweed

Maine’s hearty pod-bearing milkweed is an essential part of seasonal change. The stalky perennial provides annual food and shelter to butterflies in all stages of metamorphosis. The insects depend on the safe haven provided by Maine’s three types of milkweed plants: the sun-loving butterfly and common types and the purple-flowered swamp variety. Maine gardeners also plant non-native species as ornamentals or to attract butterflies. Found primarily in North America, the plant provides butterflies and caterpillars shelter, food and defense against predators. Monarchs, for example, lay their eggs almost exclusively on milkweed. After hatching, monarch larvae feed on the leaves, ingesting the plant’s toxins. This brilliant trick of nature makes both caterpillars and butterflies unpalatable to predators such as birds and small rodents. Read more

Image Description: Rogan milkweed plate


USA National Phenology Network: Taking the Pulse of Our Planet

University of Maine Cooperative Extension

Maine Sea Grant

Contact Information

Signs of the Seasons: A New England Phenology Program
377 Manktown Road
Waldoboro, Maine 04572
Phone: 207.832.0343 or 1.800.244.2104 (in Maine)E-mail:
The University of Maine
Orono, Maine 04469
A Member of the University of Maine System