L.A. at Home

Design, Architecture, Gardens,
Southern California Living

« Previous Post | L.A. at Home Home | Next Post »

How to plant milkweed for monarch butterflies

Dwindling monarch butterfly populations have prompted some gardeners to pepper their landscapes with milkweeds, the various plants in the Asclepiadaceae family on which monarchs lay their eggs. Chubby, zebra-striped monarch caterpillars gorge themselves on the plants' milky alkaloid sap, which makes them poisonous to birds.

The question for many isn't whether to grow milkweed, but how -- and which kind.

Milkweed-asclepias-curassvica In Connie Day's Santa Monica garden, a tiger-colored monarch spars with another butterfly, chasing it from a patch of milkweeds.

"The challenge is keeping the food here," Day says, noting that a few monarchs can defoliate a plant in a couple of weeks. Day favors South American blood flower (Asclepias curassavica), right, because it's leafy all year, unlike native milkweeds, which are dormant in winter. The South American blood flower catches the eye with brash little flowers in smoldering colors, including ember red and orange-singed yellow.

But some scientists recommend the natives. These experts suspect that the supply of exotic milkweeds is prompting some monarchs to loiter in California, and those that don't migrate seem to be more vulnerable to parasites, according to entomologist Brent Karner. And, true to their name, the nonnative plants are a bit weedy. 

The loveliest of the California natives is showy milkweed (Asclepias speciosa). Its carnation-scented blossoms are two-tiered: Five-fingered pink coronas are backed by petals that blush a rosy mauve. Velvety leaves glow in soft light. Alas, monarchs seem to prefer speciosa's homelier cousin, the narrow-leafed milkweed (Asclepias fascicularis).

So what to do with a spindly, often-bare plant? Scatter it among low-growing native shrubs, says Mike Evans, president and co-owner of Tree of Life Nursery in San Juan Capistrano.

Monarch-caterpillar "Place it behind some native grasses or irises," says Los Angeles County Arboretum and Botanical Garden Curator Jill Morganelli. "That way you can still see the flowers but you miss a lot of the 'skeletonization' that happens because the caterpillars don't eat all the way up to the flowers."

Look for a sunny place -- away from pets and traffic -- where the butterflies can spot the plant from above. After seeing and smelling a plant, they come to it and test it, biologist Bob Allen says.

"The female takes her front legs, which have chemical receptors, and scratches the leaf, tasting it with her feet to confirm it's milkweed," he says.

The aforementioned South American blood flower is widely available, as is butterfly weed (Asclepias tuberosa); but for the California species you'll have to visit a native plant nursery or troll ButterflyEncounters.com.

Start from seed to avoid systemic pesticides that some growers apply. To encourage leafy growth, cut milkweeds back after they bloom. Adult monarchs need nectar, so entice them with plantings of flat, upward-facing flowers.

There's no guarantee you'll be graced with monarchs, but Southern Californians have a good shot. Plus, milkweed flowers feed a variety of butterflies.

-- Ilsa Setziol

Photo credits, from top: Los Angeles Times; Francine Orr / Los Angeles Times; Los Angeles Times

Comments () | Archives (8)

The comments to this entry are closed.

Thanks for this important information. People everywhere should plant Bee and Butterfly friendly plants. We need them for a beautiful garden and healthy environment. Nothing more beautiful than a garden full of life!

I planted a bunch of seeds and then everthing sprouted. Milkweed grows fast and lo and behold some weeks later there were several very small caterpillars on them. some time later the caterpillars had grown like crazy and wiped out the plant, several of the caterpillars went on to become monarchs; many other caterpillars vanished to wherever. the milweed itself replenished its leaves very fast - like a weed i suppose. the cycle has been repeated numerous times.

We had these as children, its surprisingly easy to watch the crysalis open & the butterfly fly out as if I remember correctly it takes several hours.

I live in north-central Idaho and last year grew 7 or 8 showy milkweed plants from seed which had been collected locally. This species is indeed showy -- each plant produced several umbels, each with many individual flowers. (No monarchs were seen but I'm patient.) However, none produced fruit so there was no seed to collect. Each flower might be called a "masterpiece" of design, but pollination, from what I've read, is not necessarily easy for the genus. If you don't have a dissecting microscope, there are many web sites with excellent close-up photos worth a look.

Great post!

Thanks for the great article on Butterflies, I live in the Gulf area of America and we have different varieties. Unfortunately many butterflies are becomming extinct, they are so beautiful and colorful. Even the caterpillers are very pretty.
Thanks again for the info.
Stephanie Dolen

flowers are the source of love and joy,,,

Great article Ilsa and thanks for the mention of our website! We just referenced your article on our Facebook page:


Kind regards,

Bobby Gendron


Recommended on Facebook


L.A. at Home in Print

In Case You Missed It...

Hot Property


Recent Posts
New home for L.A. at Home |  July 17, 2012, 3:45 pm »
The Scout: What's new on Pico Boulevard  |  July 13, 2012, 8:22 am »
Review: Insteon remote-control LED light bulb |  July 10, 2012, 8:28 am »