Deciduous trees are those that lose their leaves and are bare for at least a portion of the year. In cold climates, this means fall through the winter to early spring. Note that plants that drop their leaves in a northern climate may retain their leaves in a warmer region of the country. In deserts, plants often loose their leaves at the start of the dry season.

Evergreen trees and shrubs, conversely, retain most of their leaves throughout the year. Most conifers (cone-bearing trees) are evergreen. However, there are a few species of conifers that are deciduous, e .g. bald cypress (Taxodium distichum), larch (Larix spp.) and dawn redwood (Metasequoia glypostroboides). 

There are two general categories of evergreen trees and shrubs – narrow-leaved and broad-leaved. Narrow-leaved trees, e.g conifers, are predominant in cold, northern climates, where they are better adapted to water loss and other stresses.  Broad-leaved evergreens include such important garden plants as rhododendrons and hollies.