Boxwood's dense foliage, tolerance for trimming and maximum growth to 5 feet tall and 5 feet wide make them good choices for hedging, screens, topiary and marking off beds with parterres. If it's emerald color you're after, consider slow-growing 'Suffruticosa' English boxwood, shown here. Or, for variegated leaves, go with Elegans boxwood, which features small, white-margined evergreen leaves and tiny, star-shaped flowers.
Boxwoods prefers partial shade, but can tolerate full sun if they kept sufficiently moist. Well-drained soil is a must.