The river birch (Betula nigra) is a useful ornamental species that has some distinct characteristics. Found growing further south than any other native birch species in the United States, the river birch often grows near bodies of water. It prefers moist soils and is a tree that landscapers use both to prevent erosion and as a specimen and shade tree.
The most outstanding characteristic of the river birch is its attractive bark. The bark exfoliates on younger trees, falling away in flaky strips, revealing the multicolored layers of the inner bark. It ranges from orange to light brown to cream-colored, and the way the bark peels haphazardly in every direction gives the river birch great visual appeal. The bark of younger river birches is a reddish-brown combination while the much older trees develop a brown bark full of furrows and ridges.
River birch leaves also are an striking characteristic. The foliage alternates on the twigs, and the University of Connecticut Plant Database describes river birch leaves as having a diamond shape. They are a glossy green, but in the fall during a good year, the foliage changes to golden yellow. The shape of the leaves combined with the long stems allows any breeze to cause them to flutter back and forth.
A river birch can grow to be as tall as 70 feet, providing that its trunk does not split into different stems. The single-trunked river birch can attain such a height in the open. But the river birch trunk may divide a few feet up from its base, creating a multi-stemmed tree. In such instances, the tree will struggle to reach 50 feet but will have a spread of about 40 feet, says the Ohio Department of Natural Resources.
Most birch species occur in the Northern states or in high elevations, meaning they are more suited for chilly climates. But the river birch grows as far south as Florida and can handle the hot weather. The tree will drop some leaves to conserve moisture in extreme drought, and one of its assets is that it resists an insect known as the bronze birch borer. Other ornamental birches in warm climates fall victim to this insect and the problems it causes, but the river birch seldom does.