Wilted foliage usually indicates too little water. Sometimes leaves become dull or otherwise off- color. Sometimes they curl and brown. Experienced gardeners usually pick up such nuances with a glance, but it probably is the most difficult challenge for others. New plants, however, need watering before they reach the stress stage.
Some species take one to two years, or even more.
Until you're sure, give them close attention. Don't try to water on a fixed schedule. And never forget that watering procedures probably top the list of cultural practices harmful to newly planted trees and shrubs. The original advice from the nursery is usually to water every couple of days after planting. The plant looks happy for several months.