In between our recent rainstorms, monarch butterflies (Danaus plexippus) can be seen fluttering around town and all over the Fiscalini Ranch Preserve. They are finishing their overwintering stay along the Central Coast, and it is time for them to find nectar plants for sustenance, mate and find milkweed on which to lay their eggs, all while starting their returning migration.
This homeward journey usually starts in February or March and continues generation after generation to points north and east. They may travel 2,000 miles. Then this fascinating cycle begins again, with monarchs west of the Rockies returning to the Central Coast the following October. How the monarchs do this generation after generation remains a mystery, and this mystery captures our imaginations. We want them to survive!
This year, again, the monarch counts are down and, of course, we want to help this fragile insect complete its journey. Planting milkweed has become a simple and popular way for monarch fans to help out, but it turns out that planting milkweed can be a big mistake.
Planting tropical milkweed (Asclepias curassavica) can be a menace to the monarch’s survival. Tropical milkweed is the colorful one — the one sold at most nurseries. It is also host to Ophryocystis elektroscirrha (OE) a debilitating parasite that infects monarchs. It causes them difficulty emerging from their pupal cases and problems expanding their wings, and it decreases their chances of survival.
Milkweed can interrupt monarch flight patterns
Native milkweeds don’t host OE, but planting them too close to the overwintering grounds can cause an interruption in the monarchs’ flight behavior. If you plant it too close to where they spend the winter, the butterflies may not migrate before laying their eggs, disturbing their normal journey and causing year-round habitation.
Monarchs are not supposed to breed on the coast, so there is no need to plant milkweed here to help them. Winter-breeding monarchs seem to have a higher risk of mortality, and the miracle of migration is broken. Some scientists say the monarchs themselves are not endangered, but it is monarch migration that is in peril.
So the rule is: If you live along the California coast, plant nectar plants to support the monarchs migrating to and from overwintering sites; do not plant milkweed. It is best not to plant milkweed within 10 miles of an overwintering site. If you live inland, please plant nectar plants and milkweed that is native to your area to assist the monarch migration away from the overwintering sites.
There is not room to cover this subject completely, so here are some websites to check for more information, including plant lists:
Jo Ellen Butler is executive director of Friends of the Fiscalini Ranch Preserve. Ranch Update appears quarterly and is special to The Cambrian.
Mark your calendar
Native Butterfly Docent Walk, 10 a.m. to noon, Saturday, April 8 — Join Pat Brown on the Fiscalini Ranch Preserve for a walk from a butterfly’s point of view. Pat will share her photos of butterflies in all stages of development, along with fascinating butterfly facts. She’ll point out some of the native plants that host the butterflies. If you can, bring a pair of close-focusing binoculars. RSVP at www.cambriaranchwalks.com or 805-927-2202.
12th annual Cambria Wildflower Show, noon to 5 p.m. Saturday, April 29, and 10 a.m. to 4 p.m. Sunday, April 30, Cambria Veterans Memorial Building — A display of more than 500 fresh wildflower bouquets collected from the Monterey County line to the Morro Bay Estuary and from the coastal bluffs to the ridge of the Santa Lucia Mountains. Each will be labeled with common and botanical names. Experts will be on hand to answer your questions. Come and enjoy — you might even find a butterfly nectar flower that you would love to plant in your garden!