The U.S. Department of Agriculture plant hardiness zone map delineates the lowest annual average temperate experienced in different regions of North America. If you live and garden in zone 3, shrubs must tolerate lows to minus 40 degrees Fahrenheit. The black chokeberry (Aronia melanocarpa) is hardy in zones 3 to 8 and thrives in partial shade and wet or dry soil. This hardy shrub has shiny, deciduous foliage that turns deep red in fall. It blooms with white and pink spring flowers and grows to 5 feet tall with an equal spread. The northern bayberry (Myrica pensylvanica) grows to 10 feet tall and wide. This semi-evergreen has lustrous, aromatic foliage and produces long-lasting gray berries. Northern bayberries grow well in partial shade, tolerate a range of site conditions and are hardy in zones 3 to 7.
USDA zone 4 gardens experience annual lows to minus 20 degrees. The bottlebrush buckeye (Aesculus parviflora) is hardy in zones 4 to 8 and grows well in partial shade. This drought-tolerant native shrub has deciduous foliage that turns yellow in fall. It produces towers of white flowers in summer that attract hummingbirds. The cranberry cotoneaster (Cotoneaster apiculatus) is hardy in zones 4 to 7 and grows to 3 feet tall with a 6-foot spread. This evergreen produces clusters of bright-red berries. It tolerates partial shade, drought and salt and grows in a dense, mounded form.
In USDA zone 5, annual lows drop to minus 10 degrees. Shade-tolerant shrubs that thrive in this zone include the groundsel tree (Baccharis halimifolia), a semi-evergreen hardy in zones 5 to 9. This salt- and drought-tolerant shrub thrives in partial shade and grows to 12 feet tall and 7 feet wide. It produces white, fuzzy fruits that last through winter. The flame azalea (Rhododendron calendulaceum) grows slowly to 8 feet tall with a 10-foot spread. This deciduous shrub grows best in partial shade with a few hours of direct sun and moist, well-draining soil. Flame azaleas produce showy orange, yellow and pink flowers in spring and are hardy in zones 5 to 7.
To thrive in northern exposures in USDA zone 6, shrubs must tolerate average annual lows to 0 degrees. The Florida anise tree (Illicum floridanum) is hardy in zones 6 to 9 and tolerates partial to full shade. This upright evergreen grows to 8 feet tall with a similar spread and has fragrant foliage. Florida anise trees bloom in late spring with dark-red, star-shaped blossoms. The fetterbush (Leucothoe fontanesiana) is hardy in zones 6 to 8 and grows to 6 feet tall and wide. This evergreen shrub also thrives in partial to full shade and prefers moist, acidic soil. Fetterbushes have arching branches covered with reddish new growth that turns copper or purple in winter.