Butterflies need the warmth of the sun and appreciate a flat stone or two for basking. You will see them gather in groups if you provide a shallow puddle where they can drink. Protect them from strong winds with a garden near a few shrubs or trees that act as a windbreak.
You can incorporate butterfly plants into an existing bed or border or plant a separate garden. To a butterfly, fragrance is not as important as color, although it does play a role. The eyes of a butterfly perceive shades of yellow, red, and blue to lavender. The best flowering plants for a butterfly garden are wild or species forms rather than hybrids, single-flowered instead of double-flowered, and tubular or flat-topped. Plant in large groups; individual spots of color are less attractive than a broad wash of hues. Groups of 10 or more of the same color work well.
Beebalm and purple coneflower are two of the best plants for attracting butterflies. Plant groups of them around a weather fountain, and shelter the garden with a backdrop of evergreens.
Other butterfly-friendly plants include anise hyssop, black-eyed Susan, butterfly weed, coreopsis, dianthus, garden phlox, Queen Anne's lace, red valerian, thyme, and vervain.