Adult butterflies use mature foliage for protection from inclement weather, predators, or merely to rest. Therefore, shelter requierements are generally met once the butterfly garden begins to come established with foliage. Trees and shrubs provide large areas that allow butterflies to rest in between, and underneath, the leaves.
Brightly painted butterfly houses are very attractive in the garden, but unfortunately, at least for this author, do not seem to entice butterflies into the confined space they provide and are mainly for aesthetics.
Butterflies are very creatures for the most part and need a quick means of escape, so they prefer to roost in areas that are easy to fly in and out of like the branches of trees and shrubs. The areas in between the foliage gives them adequate cover and an easy to escape route if threatened by predators. In my garden the undersides of fire bush and beauty berry leaves seem to be favorite roosting spots. The large leaves of these two species also provide the butterflies a place of refuge during our frequent summer rain showers.
Some species of butterfly, such as the zebra longing, roost communally in the long, dripping, clumps of Spanish moss. Several dozen may be found resting with closed wings, close by each other and their food source, but the entire group will explode into movement if disturbed.