This is a friendly reminder to trim back your milkweed throughout the fall and winter (any and all types of milkweed) in order to prevent the spread of OE (the deadly Ophryocystis elektroscirrha protozoan) to our delicate and threatened western monarch butterfly population.
If milkweed is not trimmed back, the OE protozoans from this season will survive on the old growth and infect the new butterflies this spring. We don’t freeze here, so the milkweed does not die back on its own.
It is especially important to keep tropical milkweed cut back. I cut it back to about 6-12 inches and remove all leaves and debris under the the plant in my landscape work. This ensures that there will be no lingering OE on the leaf litter.
Native milkweed is the best to grow for our western monarchs, because it does go deciduous and lose its leaves. In the future, gardeners should only plant native California milkweed, which can be found at a number of local nurseries.
Cutting back milkweed also discourages mama monarchs from laying eggs when they should be overwintering on the coast. The flowering milkweed confuses their migration at this time of year. If when trimming back the milkweed you find eggs or caterpillars at this time, we can rescue them if you contact us at TraceRobinson.com.
To learn more, go to xerces.org/monarchs/western-monarch-conservation.