Western Monarch Butterfly Project

AUG. 2023 Update:  Monarch caterpillars (larvae) have been sighted in our Demonstration Garden as of Aug. 4, 2023, chomping away at the narrowleaf milkweed. See the photo at left (or below) for a portrait of one of these “guests.”  If the milkweeds look stripped bare the next time you stop by the garden, that’s a sign of the garden’s success! Milkweeds are the larval host plant of Monarchs, and we’re delighted that demonstration garden is already serving its intended purpose. 


Western Monarch butterflies are in precipitous decline because of habitat loss, pesticides, and climate change. The Del Mar Foundation has partnered with the Del Mar Garden Club and other volunteers in our community to encourage Del Mar residents to participate in conservation efforts to ensure that these beautiful pollinators survive and thrive.

See photos of the Monarch Butterfly Demonstration Garden’s March 2023 installation here – complete with delivery of a boulder, a truck-load of new organic soil, and lots of California native plants. Thanks to all of the Del Mar Garden Club and DMF volunteers who helped create this garden; see more information below, including the plant list.

There are two populations of Monarch butterflies in North America, “with the eastern population overwintering in Mexico and breeding in the midwestern states, and the western population overwintering in coastal California and fanning out across the west from Arizona to Idaho.” (CA Dept of Fish and Wildlife)

Why the focus on Western Monarchs? DMF and the Del Mar Garden Club want to encourage community actions to support the monarch butterflies that rely on our coastal region to survive. The western population has seen precipitous declines, and despite a modest population bounce in 2021, is still considered to be at greatest risk of extinction, according to  the International Union for Conservation of Nature (IUCN), which added the migratory monarch butterfly (Danaus plexippus plexippus) to the IUCN Red List of Threatened Species as Endangered in July 2022. In April 2022, Del Mar’s Mayor signed the Mayors’ Monarch Pledge, joining other mayors across the country to take action to help save monarchs.

Visit the Monarch Butterfly Demonstration Garden at the Del Mar Civic Center!  As part of this community project, DMF has funded a demonstration garden, planted during the week of March 27, 2023 by volunteers led by the Del Mar Garden Club at the Civic Center (north end of the Civic Center plaza). The garden includes nectar plants that attract and support monarchs, and will feature Narrow Leaf Milkweed (Asclepias fascicularis), the locally-native milkweed that serves as a host plant for monarchs. We hope you’ll visit the Garden and be inspired to take steps in your own garden to include plants that support Western Monarchs (and avoid plants that put them at risk).

In the Resources section below, you’ll find a plant list for the Demonstration Garden, additional lists of plants that are appropriate for a local monarch habitat garden, and other resources. You’ll also find additional information on Western Monarchs, including: the Monarch life cycle, conservation actions, and why it is important to use locally-native milkweed in favor of tropical milkweeds, which can harm western monarchs.

Resources for More Information

Western Monarch Call to Action
Xerces Society for Invertebrate Conservation.

This Western Monarch Call to Action identifies a set of rapid-response conservation actions that can help the western monarch population bounce back from its critically low overwintering size, and set the stage for longer-term efforts to reverse population decline due to stressors such as habitat loss and degradation, pesticides, and climate change.
Note: Xerces Society generally recommends not planting milkweed within 1 mile of the coast south of Santa Barbara. We consulted with Xerces’ agronomist to confirm the suitability of Narrow Leaf Milkweed in Del Mar gardens.

Potential Risks of Growing Tropical Milkweed for Monarchs
Learn why year-round tropical milkweed fosters greater transmission of the protozoan Ophryocystis elektroscirrha (OE), increasing the likelihood that monarchs become infected with the debilitating parasite. Recommended actions: cut back tropical milkweed in the winter and fall months, and instead of planting tropical milkweed, plant native milkweed.

Western Monarch Biology: The Monarch Life Cycle
Learn about the Western Monarch’s llife cycle, migration and wintering behavior.

California Department of Fish and Wildlife:  Monarch Butterfly
Read about the conservation status of the Monarch Butterfly in California, and recommended actions that members of the public can take to support Western Monarch recovery efforts.

Plant Lists

The Monarch Butterfly Demonstration Garden at the Del Mar Civic Center is challenged by a shallow planting bed, part of the “podium” constructed on top of the parking garage – it has a soil depth of approx. 8″.  Thus, this garden does not include some of the beautiful native shrubs and plants that you may be able to include in your home garden. See the “Native Plants for Del Mar” list for shrubs and additional plants beyond those included in the Demonstration Garden.

Del Mar Civic Center Demonstration Garden Plant List (PDF) 

Native Plants for Del Mar (PDF)
This plant list focuses on locally-native plants that support butterflies and birds,with links to additional information and photos of each listed plant.

Nectar Plants: Califonia (Xerces Society)
Note: Xerces Society generally recommends not planting milkweed within 1 mile of the coast south of Santa Barbara. We consulted with Xerces’ agronomist to confirm the suitability of Narrow Leaf Milkweed in Del Mar gardens.

Butterfly Farms (Encinitas) Plant List

Above: One of the first monarch caterpillars spotted in our Demonstration Garden, with 8+ larvae spotted on two narrowleaf milkweed plants on Aug. 8, 2023. Photo: Betty Wheeler.

Monarch Butterfly, John J. Kehoe Photography (CC BY 2.0)
Butterfly Caterpillar on Narrow Leaf Milkweed, © Mara Bickett