Some of the hardest working plants and biggest problems solvers in the garden, perennial groundcover plants are easy to grow and come back year after year. They are excellent for planting on slopes, near trees and in bare spots. Ground-covering plants choke out weeds, and often reduce time spent weeding and the expense of mulch. Groundcover plants are available in a wide selection of foliage types, bloom times and colors. Some are very decorative, providing pretty foliage and flowers, while others are primarily grown for their foliage. When buying ground-covering perennials for sale online, make sure the plants will grow in your hardiness zone. Other considerations are their light requirements, soil requirements, water needs, mature height and spread, and flowering time (if applicable).