Hi - I'm trying to decide on a low-growing (1 foot or less)edging plant for along a walkway that borders an 8 foot deep bed. I'm thinking of lamium (dead nettle), but don't know if this will spread too far. There is already Sweet Woodruff as a groundcover in the bed that should fill up the bed and I don't want to mix two groundcovers. I'd like it to be a neat row next to the sidewalk to give it a neat appearance. Any suggestions?