The tiny plants of the annual rue-leaved saxifrage complete their brief growth cycle during the fall and spring. Instead, the stonecrops (goldmoss stonecrop, blue stonecrop, white stonecrop) are small succulents that store water in their leaves and stems.
More developed plants, such as the Italian strawflower, wild thyme (Thymus serpyllum) and white wormwood (Artemisia alba), grow where there is a minimal soil layer. The essential oils in their leaves release aromas that help protect against water loss.