By tradition we group plants into sun, partial sun, and shade types and plant them according to their light and heat tolerances. Gardeners need to know how much water a landscape plant requires in determining its usability in low maintenance landscapes. Rainfall gardening often greatly limits which species can be used successfully. The successful culture of all plant species requires that they be grown in a medium within a definite pH range and with from 10 to 14 essential nutrients in appropriate balance. Although plants may tolerate some extraneous elements and compounds, every plant species and cultivar has well prescribed limits.
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. The elements of that map were- Zones. Survival of landscape plants over winter was selected as the most critical criterion in their adaptation to the environment.