We are using a shallow birdbath on the ground as a butterfly water source. We have moistened sand and water in the bath. In this heat, it requires daily refilling to keep the sand moist and water available.
The butterflies seem to spend the most time on the butterfly bushes (buddleia) that are throughout our garden.The lantana seems to always be covered with lots of varieties of butterflies. The pentas, annuals for our area, work well for butterflies, but the deer (or rabbits?) are keeping the blooms off of ours. Perennials that serve as good nectar plants include agastache, asters, coneflowers, coreopsis, crocosmia, lavender, phlox, rosemary, rudbeckia, salvia and verbena.