* Try this foolproof planting scheme: Line a shallow, bowl-shaped 18-inch basket with moss (or use a preformed liner), fill with a good-quality potting mix, plant a 1-gallon Liriope in the center, add three 1-gallon mother ferns, and fill in around the ferns with five 4-inch impatiens and three 4-inch trailers (ground ivy, moneywort, variegated Vinca major).
If yellow carpets of fast-spreading, long-blooming flowers are what you want in a ground cover, consider these two easy-to-grow perennials: moneywort or creeping Jennie (Lysimachia nummularia) and goldmoss sedum (S.