Monarch Caterpillar. Photo Courtesy of Courtney Celley / USFWS. 

November 24, 2021

By Jenna Allred, Senior Manager of Climate Change Adaptation

Monarch butterflies should be arriving to the Central Coast soon for overwintering, where they will stay to breed in February. After breeding, monarchs head north to find their summer sites. Read on to learn how you can attract Monarchs to your garden this winter and help support their population. 

The most important step is to create healthy habitat for the butterflies. This includes planting native milkweed, providing nectar plants near their overwintering sites, and having trees or bushes for the monarchs to seek shelter in.

Plant Native Milkweed

First and foremost, monarchs cannot reproduce without native milkweed. Adult butterflies lay their eggs on the plant and caterpillars feed on it when they hatch.

If your garden already has a diverse range of nectar plants but lacks milkweed, you might investigate planting some. Narrow leaf milkweed (Asclepias fascicularis) is available at most nurseries and is found in most habitat types. Late fall to early winter is the best time to seed milkweed, especially before rainfall. You may also plant container milkweed in late winter if the soil is moist. It is important to note that it is not recommended to plant milkweed if you are within 10 miles from the coast. 

Be sure NOT to plant tropical milkweed (Asclepias curassavica). Tropical milkweed does not die back in the winter, allowing a protozoan parasite to thrive on it and infect monarchs. High levels of the parasite can impact the success of monarch migration, so when you are picking up milkweed, be absolutely sure it is our native milkweed and not tropical milkweed. 

On The Santa Lucia Preserve, it is not unusual for us to find milkweed already growing in the grasslands, savannas, and along riparian areas. If your lot has one or more of these habitats, there is a high chance you have milkweed already. In these areas, focus on adding nectar plants for adult monarchs to feed on. 

Provide Nectar Plants

Fall to early spring blooming plants provide reliable nectar sources while monarchs are in the area. Coyote brush (Baccharis spp.) and manzanita (Arctostaphylos spp.) provide excellent nectar during the fall leading up to winter. Species that bloom in the winter to spring, such as Bluedicks (Dichelostemma capitatum) and willow species (Salix spp.), provide nectar after the fall blooming species have finished. A site with various species that bloom at different times provides the best habitat for monarchs. 

The best seeds for your monarch garden project will be locally sourced. Pacific Coast Seed company usually offers seeds that are sourced from the surrounding area. Rana Creek Nursery tends to have nectar species in containers ready to plant, and their horticultural professionals can assist you with plant selection, establishment, and care guidance. It is best to seed before rainfall and plant containers when the soil is moist.

Provide Shelter & Diversity

When choosing a site to enhance monarch habitat, look for an area that has trees or shrubs nearby. Adult monarchs depend on these plants for shelter at night and when bad weather blows in. 

After you have seeded or planted species to enhance the habitat for monarchs, make sure you monitor and maintain the plants. You will want to keep an eye out for any species that have a hard time establishing and make sure to remove invasive plants that may be competing for resources.

In general, having a diverse range of plants in your garden makes it more desirable for monarch butterflies. Plant diversity helps prevent milkweed diseases and discourages herbivores from foraging milkweed. 

Please let us know if you’ve had success attracting monarchs to your garden on The Preserve! We’d love to see where the butterflies are most active and which plants they prefer. Send your photos to Communications & Outreach Coordinator Alix Soliman at asoliman@slconservancy.org