The River Birch
Learn why the southernmost birch is the one most popular for landscaping.
River birch (Betula nigra) is a well known and widely used landscape plant. Most of us are not familiar with this American native in its natural environment. When you bring a tree into your landscape, understanding where it came from can help you understand how to care for it.
River birch is a medium sized tree, reaching forty to seventy feet tall, not quite as wide. The trunk tends to form multiple large arching branches near the ground, and it generally is grown in landscapes with multiple stems. The bark exfoliates in sheets of tan, brown, copper or reddish-brown colored papery sheets in early years. As the tree matures, the bark at ground level becomes brown and furrowed. The leaves are a lustrous medium green, turning shades of yellow in fall. River birch is grown for its beautiful bark, handsome structure and light, airy shade.
River birch (a.k.a red birch) is native to nearly all of the southeastern quarter of the U.S., from Massachusetts to Texas and all of the major river valleys in between, following the major river valleys into the Midwest as far north as central Minnesota and Wisconsin. In the South it is absent, or nearly so, in the higher elevations of the Appalachians and along the coastal plain. This is the southernmost of the birches, preferring the silt-laden bottomlands of the slow moving Mississippi and its tributaries, instead of the rushing streams and cold clear lakes where its birch relatives are found. In its home range, it grows sparsely among silver maple, black gum and sycamore.
Although river birch has never been known commercially as a great source of lumber, it has been historically used for specialty projects as diverse as wooden ware, furniture, ox yokes, wooden shoes and hoops for rice casks. Today it is used minimally in the paper industry, for artificial limbs and for children’s toys. River birch is most helpful to us as a living tree, it beautifies our landscapes and has even been used quite successfully on strip mine reclamation sites.
River birch is well suited to areas that may be wet in spring and dry late in the season (consider its natural habitat that gets flooded in spring and often quite dry by fall). It requires full sun. It is not exactly drought tolerant, dropping interior leaves in reaction to this stressor, but it does rebound seemingly unaffected. It prefers a mildly to highly acidic soil (pH 6.5 or lower), and the leaves will become off-colored in a higher pH setting. Both container-grown and balled-in-burlap trees transplant readily. Though often used to some degree of success in parking lot islands, River birch performs better in less-constrained sites where the roots can explore further.
Keep river birch well mulched to conserve soil moisture and minimize late summer leaf drop. Pruning is seldom required, but do so in the summer if necessary. Pruning in winter will cause the tree to “bleed” sap heavily. River birch trees have no major pest problems.
A Few Landscape Cultivars
- ‘Little King’