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.