Evergreen trees retain their needles or leaves throughout the winter, as opposed to the deciduous types that shed their leaves. Conifers such as the western white pine may keep the same needles for as long as 4 years, according to the "Trees of North America" field guide. Others, like the redwood, sequoia, spruce, hemlock and fir, will not drop their foliage when it turns cold. Different trees that have leaves also follow suit, maintaining their leaves despite the turning of the pages on the calendar.
Live oak is the Georgia state tree and its leaves remain on throughout winter across its range in the southern states, which extends as far to the west as Texas. It gets its name from its leaves hanging onto the branches until, one by one, they gain replacements in the spring months. Live oak has a cousin, myrtle oak, which is an evergreen species with range including the Gulf Coast of Alabama and most of Florida. The laurel oak of the Midwest keeps its leaves, even as they change from green to a brownish-yellow, through the winter as well.
The leaves of the southern magnolia stay on the tree year-round. They are thick and have a leathery feel to them, with a glossy green upper surface and a duller underside. Sweetbay is a type of magnolia that in the northern part of its geographical range sheds its leaves, while managing to remain evergreen in the southern states where it grows. The upper surfaces of these leaves are green, but the underneath surfaces have a frosted appearance. The sweetbays of the North are only about half the size of the specimens that exist in the South.
Mountain laurel can grow to the size of a small tree across much of its range in the eastern states. Those in the southern sections of the Appalachian Mountains may be much taller than the typical 6- to 12-foot individuals that grow on slopes and hillsides in northern states like Maine and New Hampshire. American holly, which grows in the Deep South and through Southern New England, may attain 50 feet in height. Its evergreen leaves have a sharp tip, and the edges possess spiny protrusions, as anyone who has handled them will attest. Dahoon is another holly species that grows in the South, with oblong evergreen leaves. The mangrove trees that flourish in brackish water along the Florida coast are evergreen as well.