- Author: Kathy Keatley Garvey
Is tropical milkweed, Asclepias curassavica, a "bad" plant? Should Californians pull it from their gardens?
No, say many scientists, including Hugh Dingle, professor emeritus of entomology, behavior and evolution at UC Davis.
Professor Dingle is an internationally known expert on animal migration. He's researched animal migration for some 50 years. In the last 20 years or so, he has focused on monarch butterflies. He has authored two editions of Migration: The Biology of Life on the Move and some 100 papers. National Geographic featured Professor Dingle in its cover story...
- Author: Kathy Keatley Garvey
It's Wednesday afternoon, Nov. 1 and a female monarch butterfly flutters into our Vacaville pollinator garden.
Me: "Welcome Ms. Monarch! Aren't you a little late for the migration?"
Ms. Monarch: "No, I'm just a late bloomer,. so to speak. I'm heading to Santa Cruz to join my buddies for the winter and then we'll return in February. Right now, I need some nectar, a little flight fuel, to make it to Santa Cruz, if you don't mind."
Me: "Help yourself, Ms. Monarch. Right now we have several plants blooming, including Mexican sunflower, tropical milkweed, zinnias, blanketflower, catmint, roses, foxgloves, and evening primrose. One of your sisters passed...
- Author: Kathy Keatley Garvey
And just like that, a female monarch butterfly fluttered into our Vacaville pollinator garden this morning, Aug. 10, and left a dozen or so calling cards: precious eggs.
We earlier saw a male monarch patrolling the garden on the morning of July 23, but he left to go find the girls.
So, total number of monarchs sighted in our garden so far this year: 2. (In 2016, we counted more than 300 eggs and caterpillars.)
Ms. Monarch deposited eggs on three milkweed plants: a narrow-leafed milkweed, Asclepias fascicularis, and two tropical milkweeds, Asclepias curassavica. She favored a lone tropical milkweed thriving in a planter. It's already attracted honey bees, leafcutter...
- Author: Kathy Keatley Garvey
Do monarch butterflies know what they want/need?
Apparently so, from personal observation.
Over the years, we've grown multiple species of milkweed in our pollinator garden in Vacaville, Calif. We give them a choice. The species include:
- Narrow-leafed milkweed, Asclepias fascicularis
- Showy milkweed, A. speciosa
- Pleurisy root, A. tuberosa
- Tropical milkweed, A. curassavica
- Hairy balls or balloonplant, Gomphocarpus physocarpus
Which species do they prefer? Tropical milkweed, hands down. But it's a plant that's become highly controversial...
- Author: Kathy Keatley Garvey
Fact: Milkweed is the host plant of the monarch butterfly, Danaus plexippus.
Fact: Without milkweed, no monarchs.
Yet a milkweed species that's been thriving in California for more than a century is getting a bad rap. The California Department of Food and Agriculture (CDFA), apparently influenced by conservation groups, has categorized Asclepias curassavica, commonly known as tropical milkweed, as "a noxious weed."
That means, among other things, that county agricultural commissioners can ban the sale of tropical milkweed in nurseries. Indeed, several counties, including Marin, Contra Costa, San Mateo and Ventura, already...