I happen to love adding groundcovers but be warned that they will creep into your lawn so unless you put in a good border of landscape timbers, rock or metal edging the creep will flow to the lawn area. You need to pull up the groundcover each spring as it nears the lawn. There are some slower growing groundcovers for the shade such as ajuga 'Black Scallop' and lamium 'Aerium' and the slow growing Black Mondo grass or you can try native ferns with some boulders and encourage the moss for a Japanese garden look. Keep growing, Marianne Binetti