By Annina Puccio, co-founder and co-director of the Monarch Milkweed Project
Annina Puccio and Ann Whittemore started the Monarch Milkweed Project out of Benicia, CA, to increase the supply of milkweed available to Western Monarch butterflies as they make their way along their migratory path. We partnered with the Monarch Milkweed Project for an informative talk on Monarch butterflies, their population decline and how you can help! You can watch the video from the talk at the bottom of this blog post.
It has been a very successful spring and summer here in Solano County, spreading the word about how to support the Monarch butterfly population locally and spotting many of these iconic insects floating through our yards this year. Winter is the season to clean up the milkweed garden, as the last few caterpillars pupate in the fall and the final Monarch butterflies take flight for their over-wintering sites. It is also the time to begin preparing the garden bed for next year!
With shorter days, and chillier nights, native milkweed begins naturally to yellow and collapse. The roots continue to store energy for next year, so keep them watered and your plants should come back bigger and stronger than ever in the spring.
Native narrowleaf milkweed
However, if you have been growing tropical milkweed (asclepias curassavica), it is recommended that you remove it and replace it with native milkweed now. At the very least, cut the plants back almost to the ground. This variety of milkweed remains evergreen and even may flower through the winter, which allows the protozoan parasite Ophryocystis Elektroscirrha (“OE”) to build up in the plant. This disease affects the Monarch butterflies’ overall fitness, reduces their ability to reproduce successfully, and can interfere with their migration. Instead, look for seeds of native milkweed. In our local area, showy milkweed (asclepias speciosa) and narrowleaf milkweed (asclepias fascicularis) are the recommended varieties to grow, so collect seeds to sow now or in the early spring.
When planting milkweed, the seeds need “stratification,” which is the process of breaking down the seed coating with moisture and cold temperatures. If you plant seeds directly outdoors now, the rains and winter cold will stratify the seeds naturally, and they will develop strong root systems by spring.
A very good resource for fall planting instructions can be found on the Monarch Butterfly Garden website, at https://monarchbutterflygarden.net/fall-planting-milkweed-10-steps/
Alternatively, you can store moistened seeds in the refrigerator for a few months throughout the winter (lay them out on moistened paper towels in layers in a large flat container), and then start them indoors in the spring in small pots or starter cells. Keep them warm and watered, and when they have 3-4 sets of leaves, plant them outdoors after the last frost has passed.
While you are planning your milkweed garden, do not forget about nectar plants to attract and nourish the butterflies. You can find a good list, tailored to California, by the Xerces Society at: https://xerces.org/publications/plant-lists/monarch-nectar-plants-california
While you are looking ahead to next year, a fun and educational winter activity is to visit a Monarch overwintering site. The most well-known and largest are at Natural Bridges, Pacific Grove (those are pictures of the Pacific Grove Butterfly House above), and near Pismo Beach, but they also have been spotted nearby on Mare Island and at Point Pinole. Use the map from Western Monarch Count here to find a site: https://www.westernmonarchcount.org/find-an-overwintering-site-near-you/
Thank you to everyone who has worked so hard in Benicia, Vallejo and all over Solano County to support the Monarch Butterfly. The overwintering population numbers are WAY up! A 3500% increase in Pismo Beach alone.
As the Monarchs move to their over-wintering sites, we are hopeful for other increases in population as well. Keep up the good work raising Monarchs and if you haven’t already, please consider joining our Monarch MilkWeed Project group on NextDoor: https://nextdoor.com/g/our9txeuo/
Learn more about the Monarch Milkweed Project here
