Paul47-Japanese syle gardens (not actually Japanese gardens as you are confusing the 2) need to have the gravel raked, that will stop weeds and keep it fresh. Zen gardens for example tend to have no plants in them in Japan: the stones are the garden. You create a landscape with rocks that have meaning, with families keep ingstones within families for generations. You also see moss gardens and landscape ones (they tend to be inspired by 'English style' gardens - so what most people in the west think as Japanes gardens are Japanese version of English gardens). Ornamental Cherry and trees which provide differing colours throughout the year are given priminent places. So Katsura, Acers and the like, mixed with Pines and other evergreens.