Metamorphosis : Transforming a Yard Into a Butterfly Garden Requires a Few Changes in Attitude and a Little Native Intelligence
Luring local butterflies to your garden isn’t difficult--all it takes is a little work and a little luck. First, you need to provide a garden menu suited to the palate of these butterflies and their larvae, since some of nature’s prettiest creatures--the deep-orange monarchs, the chocolate-brown mourning cloaks, the vibrant yellow swallowtails and the iridescent blues--and their larvae feed only on certain plants.
The harder part may be adjusting longstanding attitudes. “A lazy gardener is the butterfly’s best friend,” says Julian P. Donahue, assistant curator of entomology at the Natural History Museum of Los Angeles County.
“Make things as natural as possible--which may include unsightly plants and untrimmed hedges--while still meeting the fire codes,” Donahue says. “Allow a little fennel, cheeseweed and cudweed where it won’t offend the gardener’s sense of aesthetics and cause embarrassment with the neighbors.”
Growing native plants is the secret to attracting native butterflies, according to John Emmel, co-author of “The Butterflies of Southern California” (published by the Natural History Museum). “Most butterfly species require native plants,” says Emmel, a butterfly gardener who lives in Hemet. The problem in Southern California, he says, is that native vegetation is rarely used in landscaping.
The anise swallowtail butterfly larvae are common to native and introduced members of Apiaceae (referred to as the carrot family). The essential oils of parsley, carrot, celery and sweet fennel, as well as those found in citrus, stimulate the butterfly larvae to eat.
A native of the Americas, the passion vine, particularly Passiflora caerulea , attracts the Gulf fritillary butterfly. Gardening books warn that the drawback to planting Passiflora caerulea is that it’s susceptible to attack by caterpillars--but, without caterpillars, there are no butterflies. So butterfly gardening requires that you think of caterpillars not as pests but as infant butterflies.
This may be a radical shift for the gardener unaccustomed to tolerating chewed leaves and half-eaten flower buds (actually, a bit of caterpillar munching stimulates the growth of many crops). It also means being careful that chemical sprays and the biological control Bacillus thuringiensis (a bacterium that dooms cabbage caterpillars and tomato worms) don’t drift in the wind and kill non-target larvae.
Even though butterflies are exceptionally good at finding their preferred plant foods--”It’s now believed that every plant has a unique infrared signature that butterflies can detect and use to find a lone plant in a quarter-acre garden,” Donahue says--trends in garden planting have been known to make or break a butterfly.
In the days when Chinese elm, weeping willow and poplar were widely planted in Southern California gardens, the mourning cloak butterfly--velvety purple-brown with yellow wing margins paralleled by bright blue spots--was more common. “There’s no hard evidence,” Donahue says, “but many people say that the mourning cloak is seen less frequently today than 30 years ago. The vast majority of this is due to habitat destruction. Reduce the amount of food plants, and you reduce the number of butterflies.” The fate of native oak trees may also affect the mourning cloaks, because the butterflies like to feed on sap flows opened up by sapsucker woodpeckers.
From the 1920s until the 1960s, native (and ornamental) senna, Cassia , was widely used for landscaping in the Los Angeles Basin, and cloudless sulfur and nicippe yellow butterflies were abundant. But in the 1960s, a big winter freeze destroyed the Cassia , ending its popularity as a landscape tree--and the butterflies depending on it disappeared. Donahue has a single Cassia in his quarter-acre garden on Mt. Washington, and that tree has been found by cloudless sulfurs migrating north from San Diego, where Cassia is still planted.
Weedy native plants such as locoweeds, buckwheats and lupines--all of which are in the legume family, along with peas and beans--are home to the inconspicuous larvae of the metalmark, copper, hairstreak and blue butterflies. The presence of these small but often intricately marked and lustrously iridescent butterflies sometimes indicates the state of the local natural ecosystem’s health. When these insects are disappearing, it usually means that the larger animals in the ecosystem and the plants are either nearly vanished or gone.
The local El Segundo blue butterfly, which feeds on sea cliff buckwheat, is now on the federal Endangered Species List because its habitat has shrunk with the urbanization of the Los Angeles coast. And the Palos Verdes blue butterfly is probably extinct because its food plant, locoweed, disappeared under the encroachment of the city and efficient weed control.
But the marine blue, being a general feeder, has been able to survive the decline in its native habitat and food plants by feeding on certain cultivated plants. Its larvae feed on Cape plumbago ( Plumbago auriculata ) and the buds and flowers of wisteria; adults thrive on the Mexican fire plant ( Euphorbia heterophylla ), an annual resembling a miniature poinsettia that is also attractive to the pygmy blue. Common pigweed ( Chenopodium ) and Australian saltbush ( Atriplex semibaccata ) also nourish the pygmy blue. The common hairstreak shares its weedy mallow food plants, such as cheeseweed, with the west coast lady and the painted lady (in years when heavy numbers migrate here from Mexico) and also finds a home on cultivated hibiscus.
The largest local butterfly is the western tiger swallowtail, whose larvae prefer the leaves of sycamore, willow, poplar and possibly even birch, cherry and avocado. Other swallowtail species breed on certain Southern California chaparral plants.
Since butterfly flight is fueled mostly by flower nectar, a good array of flowering plants throughout the year is likely to bring in a sampling of butterflies. Buddleia , fittingly named butterfly bush, is the favorite of butterfly gardeners because it attracts large butterflies such as the western tiger swallowtail and west coast lady. Buddleia alternifolia flowers in spring, while Buddleia davidii blooms in mid-summer, when butterflies are more numerous.
A close second for attracting these nectar-loving insects is lantana. And flowers that open out flat--marigolds, dahlias, zinnias, Mexican fire plant, glossy abelia ( Abelia grandiflora )--provide a nectaring perch. In recent years, flower breeders have selected for appearance, favoring doubles over the old-fashioned singles, and seldom worrying about nectar production. It may be, though, that the old single types of flowers have more accessible nectar for attracting butterflies than the showier doubles. One naturalist has suggested that this was evident when the old-type single Shasta daisy was planted alongside the double type.
To invite larger butterflies such as red admirals to your garden, plant baby’s tears ( Soleirolia soleirolii ) or leave a weedy nettle in the garden. Buckeyes thrive on plantains ( Plantago erecta and Plantago lanceolata ), monkey flower, penstemon and snapdragons.
Besides planting edibles, adding a body of water to your yard might help to garner a few butterflies too. Groups of swallowtails and other butterflies occasionally form “drinking clubs” along the edges of shallow pools that resemble creek beds. The butterflies may be seeking salts, such as those leached from manure, from the moist sands surrounding the water.
Another way of attracting butterflies is to provide rockeries. Butterflies are much like lizards in their liking for sunning themselves on rocks, particularly on cloudy days or when the weather is cool. And many trees and shrubs tend to become night-roosting spots. A few select Palos Verdes eucalyptus trees have been known to attract large numbers of migrating monarchs.
Even if you don’t grow the plants that larvae feed on, it would be hard for you to go wrong planting the flowers and trees that feed the colorful adult butterflies. The food plant index of Emmel’s “The Butterflies of Southern California” will be of further help to you in planting the right foods for local butterflies. Plants and seeds for native plants are available from the Theodore Payne Foundation, 10459 Tuxford St., Sun Valley 91352.
