By definition, evergreen trees are never without leaves, whereas deciduous trees spend part of the year without foliage in response to cooler or dryer climatic conditions. Most broadleaf rainforest trees and shrubs, along with conifers, palms and cycads are evergreen. Some subtropical or tropical trees are difficult to place in either an evergreen or deciduous category, being described as semi-evergreen or semi-deciduous; the two terms being about equivalent, although the latter is more commonly used.
In meaning, both terms indicate that a tree is without leaves for a short period of time, often associated with flower production. Evergreen trees do shed their leaves, but gradually and not all at once. Individual leaf persistence in evergreens ranges from a few months to several decades. In the middle and higher latitudes, broadleaf trees and shrubs are deciduous. Evergreen trees or shrubs have multiple applications in landscaping.
They offer a wide variety of foliage types giving different textures as desired and many have showy flowers and fruits which enhance any garden. In subtropical and tropical zones, shade is an important concern for both beauty and for practical considerations. Evergreens deliver different levels of shade (light, moderate or dense) depending upon the crown compactness, for lawns, gardens, patios, houses, other structures and street/road sides.
Evergreen tree shading of air conditioned buildings have a cooling effect and can make a significant contribution to lessening energy costs in warm or hot climates. Evergreen trees are also effective in improving air quality, acting as lungs to remove carbon dioxide from and to add oxygen to the atmosphere. The shade cast by evergreen trees also lowers ground surface temperatures and in the process decreases evaporative water loss from the soil. More information about Shade Trees can be found in the Blog of that title.
Treeworld has in stock about 140 species of evergreen trees and shrubs of varied sizes and types from which to select the best plants for landscaping any residential, commercial or public location.