Summary
River birch (Betula nigra) is a deciduous tree that is heat tolerant and offers year-round ornamental interest. Growing quickly, it can reach heights of 40-70’ and spread 35-45’ wide. It has a densely twiggy, rounded to irregular shaped crown. Often grown as a multi-trunked specimen, it can be maintained as a single trunk if desired. The bark of river birch is notable for its color and exfoliating character. Creamy–white to light–tan colored outer bark exfoliates in delicate, tattered paper-like sheets to reveal the inner bark in colors of reddish brown, salmon pink, and cinnamon on young trees. As the tree matures the bark darkens and becomes furrowed, creating an attractive ragged appearance. The ornamental bark and twiggy branching habit create a striking winter silhouette against the landscape.
The leaves of Betula nigra are somewhat diamond shaped and 2-4” long by 1-2” wide. They have coarsely toothed margins and mature to a lustrous dark green during the growing season; autumn color can be a decent light yellow but usually does not last long. The flowers of river birch are borne in floral clusters known as catkins and are displayed at the tips of the branches. Male catkins are about 2-3” long, slender, cylindrical and pendulous. Female catkins are about ¼ – ½” long, also cylindrical, but are stubby and held upright. Blooming occurs in mid– spring, as the leaves emerge, and flowers are wind pollinated. Ripened seeds, technically known as winged samaras, are also dispersed by the wind. Seed are eaten by song and game birds. As a keystone species, river birch hosts hundreds of native caterpillar species.
The common name, river birch, alludes to this tree’s ability to grow in moist to wet conditions, tolerating even periods of inundation. Well-drained, acidic soils in full sun to partial shade are best. It will tolerate black walnut, urban conditions, heavy clay soils and some drought once established. It makes a wonderfully architectural shade tree and is equally effective planted along a pond or stream edge. An apt choice for soil stabilization for a swale design planted with sweet bay (Magnolia virginiana), possumhaw viburnum (Viburnum nudum), and sensitive fern (Onoclea sensibilis). Zones 4-9.
More Details
- Plant Type
tree - Sun/Shade Conditions
full-sun-to-partial-shade - Foliage Character
deciduous - Soil Moisture
average-to-wet - Flowering Period
mid-spring - Soil PH
acidic - Flower Color
inconspicuous - Summer Foliage Color
dark-green - Fall Foliage Color
greenish-yellow - Other Common Names
River birch, Red birch, Black birch, Water birch - Fruit/Seed Color
reddish-brown-tan
Additional Information
Missouri Botanical Garden, Illinois Wildflowers, Lady Bird Johnson Wildflower Center,