Attracting Butterflies in El Dorado Co. Foothills

by Dr. Arthur M. Shapiro, Section of Ecology and Evolution, UC Davis
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Butterfly gardening in the foothills is different from butterfly gardening in the Central Valley. In the Valley, most of the butterfly species are weedy, highly dispersive, multiple to brooded, reach highest densities in the autumn, and depend on a combination of introduced plants (both weeds, and cultivated species), and irrigation for their continued presence. In the foothills, though some of these weedy species still occur, most of the butterflies are native, adapted to the foothill climate and thus restricted to one or two broods a year in the spring, and less likely to feel at home in a garden. You have many more species nearby in the foothills, but may have a lot less action to see in your garden!

Your strategy and success gardening for butterflies in the foothills will depend heavily on your landscape surroundings:

Urban/Suburban: Most similar to butterfly gardening in the Valley, since most of the vegetation is "artificial". Because winters are colder (and summers may be warmer, without maritime influence below 1200 ft. near the Delta), some of the weedy butterflies may be excluded, or may show up only late in the year and erratically as overflow from the Valley. The farther you are from natural vegetation, the harder your job of attracting native species to the garden.

Ranchettes: Isolated homes on large lots often have quite a bit of grassland, with scattered native trees, mainly oaks, maybe buckeye. The trees may sustain some butterfly populations but much of the annual grassland is dominated by weeds not useful to butterflies, and its fauna is likely to be poor. Rocky areas have richer native floras and more butterfly species; so do creek bottoms. Hog wallows (ephemeral ponds in low areas between hills) may have good plants but do not support special butterflies in our area. If your lot is dominated by yellow star thistle (condolences!), it is a superb nectar source and there is little point in supplementing it in the garden to what you see on it is what you'll get.

Semi to Natural: Where homes are interspersed within more or less intact landscapes, gardeners can tap into the resident fauna, whatever it is. There are few resident butterflies in the forest, per se. Most occur in clearings, along roads, and by streams, The highest diversity in our area always occurs on rocky canyon walls with a high diversity of flowering plants. Typically, streams that flow E to W have richer butterfly faunas than those that flow N to S because there is greater vegetational difference between N to and S to facing slopes and each plant community brings its own fauna. If you live in or near such a canyon you may see from 40 to 70 species at or near your home! If you live on a special soil (serpentine, gabbro, or limestone) you may get rare species not found elsewhere. There are very special butterflies that, as larvae, feed on MacNab cypress, lLeather oaks, serpentine scrub oak (Quercus durata), pine mistletoes, etc. Watch for them.

With so many local situations to take into account, gardening hints for the foothills can only scratch the surface. Keep the following in mind:

Few butterfly species can maintain an ongoing population within the confines of a residential lot, even a big one. If you get breeding, it will be as part of a larger “metapopulation”: whose borders are constantly changing. Remember that an ongoing population requires larval host plants, pupation sites, adult food supply, and mating sites (which may require male territories).

The principal function of a butterfly garden is to intercept individual butterflies as they move through an area and detain them where they can be observed and enjoyed. Occasionally, one can actualy boost numbers by planting nectar sources or larval hosts if these are in short supply. More often, one is just moving individuals around, from one place to another.

Valuable natural history data can be obtained from a butterfly garden. Skillful planting will enable you to maximize both the number of individuals and the number of species you see, but be realistic in your expectations; don't expect endangered species to breed in your backyard.

Suggested Plants for Foothill Butterfly Gardens, by intended function:

Larval Host Plants for Native Butterflies:

NATIVE and NON-NATIVE NECTAR PLANTS:

SHRUBS:

PERENNIALS:

ANNUALS:

THIS LIST IS BY NO MEANS EXCLUSIVE. TRY EXPERIMENTING.

PS: MORE WEEDS THAT BUTTERFLIES LOVE