16 Shade Planning for America’s Schools Chapter 2 Disadvantages • Vegetation takes time to grow. • Trees can create litter, such as leaves, nuts, and fruits. Considerations • There are regional differences in vegetation. Plants native to a particular region have evolved to thrive in the conditions prevalent there. Whenever possible, locally grown native varieties of trees, shrubs, and vines should be used in the design. The United States Department of Agriculture (USDA) Cooperative Extension Service agent in your area can help determine the best species for your design. • The effectiveness of trees and vines in providing UV radiation protection is directly related to the density of the plant’s foliage. • As a rule of thumb, trees should be planted to the south and west of where you want to shade so they can provide it during the midday and afternoon hours. Chapter 5, “The Earth-Sun Relationship”, gives information on creating shade in the right place at the right time. • Some plants are poisonous or cause allergic reactions. Other plants can attract bees or have dangerous spikes or thorns. One needs to become familiar with the possible harmful effects of the species that are being considered. • Trees may interfere with a school’s electrical service, plumbing, and drainage systems. Care should be taken that vegetation is not planted where it might later present a threat to the school’s utility systems. • Many trees will not tolerate root compaction, which occurs when foot traffic compacts the soil around the roots of a maturing tree. Several strategies will prevent it, including a temporary fence around the maturing tree or specially designed pavers to absorb the impact of busy feet. • A short-term or transitional structure can be built to provide shade while the vegetation is maturing. • The first year after planting vegetation is the most important for ensuring the survival of trees, shrubs, and vines. Plants must be watered at regular intervals if rainfall is inadequate. The USDA Cooperative Extension Service agent in your area can help you determine an appropriate watering schedule. • Some communities have restrictions on water use that might affect decisions on which plants would be most appropriate. Transitional shade Designed by Shade ‘n’ Sails of Victoria, Australia Where Can I Find More Information? Chapter 5, “The Earth-Sun Relationship”, gives more information on providing shade at the right place, at the right time, throughout the year. The following pages contain links to information about selecting trees, vines, and shrubs; sources for plants and products related to natural shade strategies; information on creating natural wildlife habitats; organizations that manufacture and install fabric shade structures; and contact information for the USDA’s Cooperative Extension Service.