It looks like sweet alyssum, but is not even close. The tiny white flowers and finely textured foliage work almost as well for similar uses in the landscape. In fact, the plants are most often grown as short term warm season annuals. However, candytuft, Iberis sempervirens, is really a perennial that can be cut back in autumn, regenerate through winter, and bloom for spring and early summer.
One must really examine candytuft closely to see that it is related to cole crop vegetables like broccoli, cauliflower, cabbage and Brussels sprouts. That is why is has an odd aroma when cut back. Mature plants have the potential to get nearly a foot deep, but typically stay lower. They can spread a bit wider than a foot. Candytuft can tolerate a slight bit of shade, but prefers sunny exposure.
If planted closely together, candytuft can form a nice small scale ground cover. It mixes nicely with stones, and cascades slightly over the edges of low stone retaining walls. It is more substantial than sweet alyssum, and works better for permanent planting in borders and along walkways. The barely perceptible floral fragrance of individual plants can be quite appealing in larger volumes.