Mowing & Habitat Management

Why isn't the milkweed growing in my habitat flowering?

Different species of milkweed have different growth strategies, so it depends on what species you have. In general, milkweed may not flower in the first year of growth because it is investing its resources in growing a strong root system. Also, if there is excess nitrogen in the soil, the plant may not flower, so do not fertilize milkweed. Finally, milkweed may not bloom if the plant is stressed, such as by drought or excessive heat. Luckily, monarchs will lay their eggs on milkweed even if it is not flowering! The caterpillars eat the leaves of the plant, so your milkweed can still be a host plant without flowers. Milkweed may also spread through its root system (depending on the species), so the plant may spread that way despite not flowering or going to seed.

What should I do if I haven't seen any monarchs in my milkweed patch?

Because monarchs are distributed across a very wide range, and there are so many fewer monarchs than there were previously, it can take a long time for monarchs to find a patch of milkweed. However, if you live in the monarch's breeding range, your milkweed is important! It is vital to get as much milkweed as possible out on the landscape, so that the monarchs that are out there are the most likely to find viable habitat in which to breed.

There are a few things you can do to make your habitat more enticing to monarchs, which may help them find your habitat.

1. Plant a variety of milkweed species. This gives females multiple options when choosing a host plant for their eggs. Find species of milkweed native to your region here, and find sources of milkweed plants at www.plantmilkweed.org.
2. Plant a variety of flowers that bloom throughout the season. Adult monarchs need to eat the nectar from flowers. See the Xerces Society Monarch Nectar Guides for regional recommendations of monarch-preferred nectar flowers.
3. Provide shelter from the wind and sunny places for monarchs to bask. This handout provides other general recommendations on gardening for monarchs.

Is milkweed harmful to grazing livestock?

Milkweed plants do contain toxic cardiac glycosides, but they rarely pose a significant threat to people or animals. A small taste of milkweed is typically not fatal to animals but can be dangerous if large quantities are consumed. If sufficient forage is available in grazing lands, livestock generally do not seek out milkweed. According to the USDA, poisoning typically occurs in areas of poor forage where milkweed is abundant. Prepared feeds and hay should not contain high concentrations of milkweed. For more information, please refer to our MJV handout: Monarch and Milkweed Misconceptions.

I don't see many chrysalises, but I do see some caterpillars. Why is this?

You're not alone if you haven't seen many monarch chrysalises in the wild. Monarch caterpillars usually move away from the milkweed plant they were eating when they are ready to pupate, or form their chrysalis. Chrysalises are found on a variety of different plants and structures within the habitat, like benches, windowsills, and other nearby plants or bushes. If you had been seeing large instars and expect they should have transitioned into the chrysalis stage but haven't seen any, don't fret. It is rare to find monarch chyrsalises in the wild, so just because you didn't see them doesn't mean they weren't successful. Keep records about what you are observing through programs like the Monarch Larva Monitoring Project, www.mlmp.org. If you find monarchs one week and the late instars are gone by the next week and you aren't successful in finding their chrysalis, use your knowledge about monarch biology to watch for freshly eclosed (emerged) adult butterflies about 10 days later.

When is the most appropriate time to cut tropical milkweed back?

It is recommended to prune the milkweed stalks to about 6 inches in height during the fall and winter months to discourage monarchs from establishing winter-breeding colonies. Cutting back the milkweed will also help to eliminate OE spores that may be present on the plant. Re-cut the milkweed every few weeks as leaves re-sprout. Tropical milkweed might pose fewer problems in the northern monarch breeding range because it dies back naturally when it freezes.

These recommendations are not applicable in South Florida (south of Orlando), where a distinctive, non-migratory population of monarchs has long been established. However, native milkweed planting is still encouraged in this area. For more information about Florida monarch populations, read our handout Florida Monarchs: Exploring Dynamics and Habitat. 

For more information on tropical milkweed, read our handout Tropical Milkweed and OE: Potential Risks for Monarchs. 

My milkweed habitat should be mowed to cut back the woody vegetation that is encroaching. Is there a safe time to do this that will be less harmful to monarchs?

Yes! The MJV has a handout called Mowing and Management: Best Practices for Monarchs. We utilized community science data and ground-tested it with researchers and volunteers nationwide to develop recommendations for times when management activities may be safer for monarchs. It is essential to note that this handout focuses solely on monarchs. If you have prioritized additional plant or animal species to protect at your site, ensure that you consider a timing that works best for all. Because monarch timing can vary slightly from one year to the next, it is also important to monitor the migration status through Journey North to see how this year's timing compares to previous years. Most importantly, avoid mowing or disturbing the entire habitat at once, so that you leave untouched areas for wildlife to use as they recolonize the habitat.