Every plant can adapt to a range of environments.
Gardeners have learned through experience where the great variety of landscape plants can be grown. Over the years many schemes have been proposed to help gardeners locate those environments when they introduce new species, forms, and cultivars. In cooperation with the American Horticultural Society, he worked with horticultural scientists throughout the United States to incorporate pertinent horticultural and meteorological information into the map. Survival of landscape plants over winter was selected as the most critical criterion of their adaptation to the environment. The zone ratings were intended to indicate excellent adaptability of the plants.