Leslie Saul of the San Francisco Zoo offers advice on attracting them to your garden. Adult butterflies aren't picky about sources of nectar, but adults will lay their eggs only on specific host plants, on which caterpillars will feed. By learning more about which butterflies are native to your area, you can choose the right host plants. Good general nectar sources include butterfly bush, purple coneflower, Joe Pye weed, butterfly weed, ironweed, verbenas, zinnias, Mexican sunflower, cosmos, lantana and small, single-flowered marigolds. Site your butterfly garden in a sunny, warm area where the insects can sun themselves.
Stones make good sunning spots.
Butterflies appreciate some protection from wind as well. A flowing-water feature will help draw butterflies.