A successful butterfly garden consists of four items; sunshine, windbreaks/shelter, nectar/water, and larval food plants.
Butterflies prefer warm, sunny spots in the garden. They fly best when their body temperature is about 85-100 degrees -which is why they are usually seen during the hottest time of the day. Provide rocks in the garden which butterflies can perch upon to warm themselves.
Sheltering the butterfly garden from winds help butterflies so they are not cooled by winds and will not have to expend extra energy searching for food, mates, and laying eggs. Vitex agnus-castus and Buddleia's not only provide shelter but nectar as well. From a butterflies point of view you can't have too many nectar sources! Large groups of plants will be more enticing to butterflies and diversify the palette so there is always something in bloom.
According to Desert Butterfly Gardening, published by the Arizona Native Plant Society and Sonoran Arthropod Studies Institute, the following are just a few of the many plants that butterflies love to visit. Bee Bush (Aloysia grdtissima), butterflies love the nectar and the birds eat the small seeds. Pine-leaf Milkweed (Asclepias linaria), this plant is the major food source for the Queen and Monarch caterpillars. Side-oats Gramma (Bouteloua curtipendula) and other native grasses are great larval food plants. Desert Hackberry (Celtis pallida) is a native larval food plant and a good all-around wildlife plant. The Dalea species is another great larval food plant and will not only bloom in spring but many also bloom again in fall. Lantana is known worldwide as a great nectar producing plant-the yellow and pink varieties seem to attract butterflies the most.
For water, provide an area where a small dish can be filled with sand/soil, manure, and water until damp. Males will visit the site-a behavior called "puddling." They will extract sodium and other nutrients needed for mating. To keep females from just passing through (and the males, too) be sure to include larval food plants, which are what they are searching for so they can mate and lay eggs. These can be planted in an informal place away from the main garden as the caterpillars will chew up the leaves and flowers leaving plants unsightly. And, remember that butterflies are insects and pesticides (including BT, Bacillus thuringiensis) kill not only the bad guys but butterflies and their larvae as well.
Sources: Desert Butterfly Gardening, Arizona Native Plant Society and Sonoran Arthropod Studies Institute; The Butterfly Book, Donald and Lillian Stokes/Ernest Williams; SABO of Bisbee, (520) 432-1388, e-mail: sabo@SABO.org. Website: www.sabo.org