Prepared by Debbie Shaughnessy, HGIC Information Specialist, and Bob Polomski, Extension Consumer Horticulturist, Clemson University. (New 05/99. Images added 11/06.)
River birch (Betula nigra) is a handsome tree native to the southeastern United States. It is considered the most widely adapted of all the birches, and hardy throughout South Carolina.
Iowa Dept. of Natural Resources
The birch is a large deciduous tree, growing 90 feet in height and spreading 30 to 50 feet.
It grows at a medium to rapid rate (30 to 40 feet over a 20-year period). It tends to be short-lived (30 to 40 years) on many urban sites, possibly due to a shortage of water in restricted areas. Birches situated in moist areas are long-lived.
One of the most appealing features of the birch is the bark, which, on larger, young branches and stems, is reddish to pinkish brown and peels off in papery strips. The exposed inner bark is gray-brown to cinnamon-brown to reddish brown. The bark of a mature birch is ridged and deepens to dark brown. This tree is handsome without leaves because of its graceful silhouette and exfoliating bark.
River Birch Bark
Karen Russ, ©2006 HGIC, Clemson Extension.
Separate male and female flowers are borne on the same tree; the male in the form of a catkin, and the female in cone-like clusters that fall from the tree and are blown for long distances by the wind. In the fall, the foliage turns pale yellow.
The graceful elegance of the birch allows it to be used as a specimen or for naturalizing, and is best used in large areas. It transplants easily and is most effective when planted in groupings. A multi-trunk specimen is more handsome than single-trunk trees. It should not be planted in high-use areas such as driveways, walks and patios, as dead branches tend to be messy. Periodic pruning is required to remove these branches; this can be done at any time of year. Pruning healthy trees should be done when the tree is dormant (late summer to before midwinter), as this tree bleeds heavily.
Although the river birch thrives in wet areas, it does not require excessive amounts of water. It tolerates fairly dry soils once it is established. It requires acidic soils, suffering from iron deficiency if pH levels are 6.5 or higher. This species requires full sun and tolerates high temperatures.
River birch may be troubled by leaf spot diseases and early leaf drop in wet climates. Various leaf miners and aphids may infest it, but these problems are unimportant. One aphid causes the leaves to crinkle in the spring. It causes no lasting damage. River birch is not susceptible to invasion by the bronze birch borer, a common problem with other birches in the south.
The most prominent of all the cultivars is 'Heritage.' It is faster-growing, has larger, glossier leaves and is less prone to leaf spot than the species. The bark exfoliates on younger trees and opens to a lighter, salmon-colored trunk.
Note: Chemical control of diseases and insects on large trees is usually not feasible since adequate coverage of the foliage with a pesticide cannot be achieved.
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This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.