The River Birch (Betula nigra) can grow to 90 feet tall and is the most popular birch for landscaping because it thrives in warmer parts of the U.S. It has a fast growth rate and can be used as a screen, border or shade tree. The attractive peeling brown and red bark adds winter interest to the landscape. The River Birch naturally grows as two or three trunks, but can be trained to one main trunk if desired by cutting away all but one trunk. Although it is an attractive tree, it is short lived and usually dies within 20 to 30 years if planted in the city. The native habitat of the River Birch is deep, moist, acidic soil.
Plant a River Birch tree in a location where the roots are shaded and the top of the tree receives more than six hours of sun each day. These conditions usually exist on the east or northeast side of structure. Planting a River Birch in a site that is hot and dry, where supplemental water cannot be provided, is not recommended.
Add a one-inch layer of compost and organic granulated fertilizer over the root base two times a year, in the spring and again in the fall. Follow directions on the fertilizer container for the amount of fertilizer to add to a tree or shrub. This can be followed by a 1-inch layer of mulch over the root zone if desired, but the mulch must be removed before adding the compost and fertilizer, then replaced.
Water deeply and frequently by running a stream of water the width of a pencil from a standard watering hose over the root system for one hour. This should be done every two weeks during the growing season if there is no rain. A River Birch appreciates damp, rich soil.
Prune the River Birch in the winter when the tree is dormant. The tree produces a multitude of small limbs and some may droop too close to the ground. Simply prune the small branches you wish to remove back to the main trunk.