Betula nigra, also known as river birch trees, is a deciduous tree that has the greatest resistance to bronze birch borers. The peeling bark of the river birch adds winter interest to its surroundings. Find facts and information on Betula nigra and some of its related species.
Facts on River Birch Trees
Birches are grown in Zones 3-9 and grow in an upright pyramidal shape. They are easily recognized by their interesting peeling bark and are often used as shade trees for large yards. This variety has a medium to fast growth rate and reaches heights of 40-70’ high by 30-40’ wide.
The bark, has a cinnamon-brown coloring. Its fall color is bright or golden yellow. It is usually used as a specimen tree, although it can be short lived in the landscape. It has good resistance to bronze birch borer. To encourage, a healthy, long-lived tree, keep its natural floodplain conditions in mind- cool, moist soil in lowlands.
If you are planting in the lawn, remove all grass in a large circle under the tree and cover the soil with 2-4” of organic mulch. Avoid exposed sites with drying wins and sites with compacted soils.
Care of Betula nigra species
You should amend the soil with ample organic matter before planting. Keep the soil evenly moist from spring until the ground freezes. Water lawn trees deeply to make sure available moisture reaches the tree roots. Trees that show signs of stress, or insect and disease problems, benefit from root feeding in spring. Remove the lower branches to enhance the appearance of the coppery trunk. Do any pruning in summer to avoid sap flow from pruning wounds made during the dormant season.
Propagation is done by planting seeds. The seeds require light for germination. Note that it is very difficult to propagate by taking cuttings.
Diseases and Pests include leaf spot, aphids, and dieback. All of these are more prevalent in trees that are stressed.
Related species include: European white birch (Betula pendula) has a pendulous growth habit, but the bark is not as showy as other species, and the tree is susceptible to bronze birch borers. Paper birch or white birch (Betula papyrifira) has peeling chalk-white bark and is also susceptible to bronze birch borer and birch leaf miner. It performs best on cool, moist shady sites.