One of the factors contributing to the decline of the Western monarchs is a lack of milkweed; milkweed is the only host plant that monarchs can use for reproduction. Because it was removed from the landscape due to development, there is a shortage of milkweed on both wild and cultivated lands. Additionally, because the plant is toxic to cattle, it was generally removed from land used for ranching.
The only species of milkweed that is native to Marin County is narrow-leaf milkweed (Asclepias fascicularis). Native milkweed plants are in such high demand in the Bay Area, that the plants are not always easy to find at local plant nurseries. SPAWN Nursery has developed an innovative milkweed give-away program to make it easy for Bay Area gardeners to add narrow-leaf milkweed to their gardens.
One unique aspect of the milkweed give-away program is that SPAWN is working with local elementary school students to grow milkweed plants at their schools.
SPAWN worked with two 4th grade classes of students at Glenwood Elementary, located in San Rafael, CA. Glenwood Elementary has been an education program partner with SPAWN for several years, and during spring 2021, worked with SPAWN to grow narrow-leaf milkweed. The 4th grade classes grew redwoods for SPAWN restoration projects in past years.
In 2021, Glenwood Elementary 4th graders germinated and cared for 200 narrow-leaf milkweed seedlings. Students took turns checking the moisture level of the soil and watering the seedlings throughout the spring. SPAWN Nursery Manager, Audrey Fusco, picked the seedlings up from the school and took them back to SPAWN Nursery at the end of the school year. 40 plants were donated to the school to support the monarch waystation, which was built by SPAWN and 4th grade classes at Glenwood Elementary in winter 2020. The remaining 160 plants were potted up into one-gallon pots and cared for by SPAWN volunteers and nursery staff through the summer and fall.
In October 2021, SPAWN invited gardeners to remove their tropical milkweed plants and trade it out for narrow-leaf milkweed, or to simply pick up the native milkweed to add to their garden. For information concerning ways tropical milkweed is harmful to the monarchs in California, it can be seen in the tropical milkweed trade-out flyer.
Tropical milkweed trade-out program participants were asked to wait until November 1st to remove the tropical milkweed to allow the monarchs enough time to migrate to the coast prior to removing plants. Milkweed giveaway participants were also requested to wait until November 1st to pick up plants so that the milkweed would be planted after the start of the rainy season. Plants were only given to Bay Area residents who live in appropriate places for planting milkweed, at least 5 miles away from the coast.
By January 2022, all 160 of the available plants had been given away to local individuals, schools, and local organizations. Approximately 50 tropical milkweed plants had been removed and replaced with native milkweed. Additionally, many new monarch waystations, which contain nectar plants in addition to milkweed, were created at local schools and businesses.
The milkweed giveaway program accomplishes multiple goals. The primary goal is to provide native milkweed plants, grown from seed that was collected from a wild population in Marin County, to gardeners so that the plants can be of benefit to monarch butterflies. Another goal is to encourage gardeners to remove tropical milkweed plants.
In addition, growing milkweed with elementary school students provides an avenue to teach about multiple themes within environmental education to students. Through hands-on learning, the students learn about the connection between butterflies and their host plants, which facilitates an understanding of the important relationship between native plants and wildlife. Additionally, students learn how to grow plants and gain the experience of caring for seedlings. Finally, students are given a sense of empowerment as they are taught methods for solving environmental problems and ways to actively engage in protection of endangered species.
SPAWN Nursery is sowing narrow-leaf milkweed seeds with three classes of 4th graders in February and March 2022. Later in the calendar year, the nursery will offer the milkweed plants to Bay area gardeners in fall 2022. Milkweed plants also provide an important source of nectar for native bees.
Monarch butterflies will benefit from the increase in milkweed plants, which are utilized by monarchs for both nectar and for reproduction. The Western monarch population declined to less than 2,000 individual butterflies in the 2020 annual Thanksgiving monarch count. In just one year, the population increased to 247,237 butterflies, as counted in the Xerces Thanksgiving count of 2021. This incredible population rebound shows that it is possible for the Western monarch to recover and that taking direct action to help with recovery of monarch populations is critical.