Bugleweed, bishop's weed, and lilly of the valley are groundcovers that grow in hardiness zone 4. Bloodtwig dogwood and red ovier dogwood are shrubs that grow in the shade in this zone. Anabelle hydrangea grows in the shade and flowers in June. Japanese and English Yews are hardy to zone 4 and thrive in shade. Deciduous azalea, lady slipper, and columbine grow well in zone 4 shade conditions.
Long cold winters and short warm summers characterize USDA hardiness zone 4. This zone includes the higher elevations of the Central and Northern Rockies, the Upper Midwest, and Northern New England. The low winter temperatures are between -20 and -30 degrees Fahrenheit. Moisture, soil fertility and wind patterns also affect what plants will grow.
Trees and shrubs compete with smaller plants for water. A tree canopy deflects rainfall from plants and acts as an umbrella. Redbud and hemlock trees grow well in the Northeast, but don't survive as well in the West and Midwest.
The USDA hardiness zone information is intended as a guideline, and gardeners should consult other resources when deciding what plants to grow. The USDA provides an interactive map that allows users to find information on their specific area. Sunset books and other gardening resources provide region-specific information.