USDA zone 4 experiences average annual lows to minus 30 degrees F. The Stand Fast maple (Acer platanoides "Stand Fast"), a cultivar of Japanese maple, is hardy in USDA zones 4 to 7. It grows slowly to 3 feet tall and 1 foot wide and has dark, ruffled foliage. This deciduous shrub thrives in full sun to partial shade and moist, well-drained soil. The Scotch heather (Calluna vulgaris) grows to 2 feet tall with a 4-foot spread. This slow-growing evergreen has ascending branches covered with small leaves that turn bronze in winter. It blooms with pink and purple flowers from summer through autumn and is hardy in zones 4 to 6. It prefers acidic soil and sun to partial shade.
In USDA zone 5, average lows reach minus 25 degrees. The Chenault barberry (Berberis x chenaultii) is hardy in zones 5 to 8. It grows to 4 feet tall with a 5-foot spread and has glossy foliage that turns coppery red in cooler months. This evergreen tolerates a range of site conditions and blooms with yellow flowers followed by long-lasting black berries. The tree boxwood (Buxus sempervirens "Arborescens") grows to 10 feet tall and 4 feet wide. This evergreen has an upright, conical form and dense, lustrous foliage. It prefers sun to partial shade and moist, well-draining soil and is hardy in zones 5 to 8.
To thrive in USDA zone 6, shrubs must tolerate lows to minus 15 degrees. The Duke Gardens yew (Cephalotaxus harringtonia "Duke Gardens") is hardy in zones 6 to 9 and grows slowly to 5 feet tall with an equal spread. This evergreen has a semiformal, oval shape and ascending branches covered with lustrous, fragrant needles. It tolerates heat and drought and thrives in well-draining, moist soil. The deciduous blue mist shrub (Caryopteris x clandonensis) grows to 3 feet tall with an equal spread. It produces butterfly-attracting blue blooms and has aromatic leaves. Blue mist shrubs are hardy in zones 6 to 9 and prefer full sun and well-draining, loamy soil.
USDA zone 7 experiences annual average lows to minus 5 degrees. The sandhill rosemary (Ceratiola ericoides) is hardy in zones 7 to 10 and grows slowly from 1 1/2 to 8 feet tall in a dense, domelike shape. This evergreen has aromatic, needlelike foliage and produces red-yellow flowers and fruits. This native plant tolerates drought and prefers well-drained soil. The weeping Himalayan cedar (Cedrus deodara "Pendula") grows to 3 feet tall and 10 feet wide. This evergreen has dark blue-green needles and pendulous branches. It is hardy in zones 7 to 8 and thrives in sunny sites with well-drained soil.