Vinca minor--also called periwinkle--is a perennial evergreen ground cover that is popular under trees and shrubs and on sloped areas for erosion control. It blooms small white, blue or purple flowers in both the spring and the fall. Before planting, till in about 3 inches of organic matter, such as compost or peat moss, to make the area more conducive to Vinca minor. Vinca minor is not the same thing as the annual plant also called periwinkle and vinca, but have the scientific name Catharanthus roseus.
Space Vinca minor 12 to 18 inches apart, which is what most gardeners do. In two to three years, the Vinca minor will completely cover the planting bed.
Alternatively, space Vinca minor 6 inches apart and by the end of the first year, the planting bed will be completely covered. Planting Vinca minor this closely together will require more pruning in subsequent years than planting the plants further apart as described in step 1.
Plants vinca minor as deep as the container it is currently in. Then, water well and tamp down the soil with your hands to void any possible air pockets, which can cause root rot.
Mulch in between the plants. This is important to not only retain water, but to also keep the weeds out. After the Vinca minor fill in the area, you will not need to mulch any more.