Prayer plants (Maranta leuconeura) are tropical flowering perennials that are often grown indoors as a houseplant. While they are relatively easy to care for, one issue you may encounter is the foliage curling into itself. Often a sign of stress or a health issue, it’s important to find and treat the cause of your prayer plant’s leaves curling so it can continue to grow and flourish. Ahead, horticulturists share the most common reasons a prayer plant’s leaves curl-and how to fix each one.