Species Native to Missouri
Common Name: river birch
Type: Tree
Family: Betulaceae
Native Range: Eastern United States
Zone: 4 to 9
Height: 40.00 to 70.00 feet
Spread: 40.00 to 60.00 feet
Bloom Time: April to May
Bloom Description: Brown (male) green (female)
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: Low
Suggested Use: Shade Tree, Rain Garden
Flower: Showy
Attracts: Birds
Other: Winter Interest
Tolerate: Deer, Drought, Clay Soil, Wet Soil, Black Walnut, Air Pollution
Culture
Easily grown average, medium to wet soils in full sun to part shade. River birch is perhaps the most culturally adaptable and heat tolerant of the birches. Prefers moist, acidic, fertile soils including semi-aquatic conditions, but also tolerates drier soils. Consider using soaker hoses and bark mulches to keep the root zones cool and moist. Adapts well to heavy clay soils and will tolerate poor drainage. Avoid pruning in spring when the sap is running.
Noteworthy Characteristics
Betula nigra, commonly called river birch, is a vigorous, fast-growing, medium-sized, Missouri native deciduous tree which occurs on floodplains, swampy bottomlands and along streams throughout the State. In cultivation, it can be trained as either a single trunk or multi-trunked tree. As a single trunk tree, it develops a pyramidal habit when young, but matures to a more rounded shape typically growing 40-70' tall. Multi-trunked trees form a more irregular crown and are generally considered to be the superior growth habit for this species. Salmon-pink to reddish brown bark exfoliates to reveal lighter inner bark. Leathery, diamond-shaped, medium to dark green leaves (1.5-3.5" long) with doubly toothed margins turn yellow in fall. Monoecious flowers appear in drooping, brownish male catkins and smaller, upright, greenish female catkins.
Genus name is the Latin name for birch.
Specific epithet means black.
Problems
One of the most disease-free birches. Most species of birch grow best in cool, northern climates, but do not adapt well to the hot summers of USDA Zones 5-9 and can be short-lived therein. Weakened birches become vulnerable to the bronze birch borer which typically infects and kills birches stressed by summer heat and humidity. River birches are Missouri natives that are naturally adapted to the climate and are extremely resistant to birch borer. Although river birches have some susceptibility to aphids, leaf miner and iron chlorosis in high pH soils, these problems are somewhat minor in comparison to the birch borer.
'Heritage' is a very popular river birch cultivar with superior ornamental features to the species (see Betula nigra 'Cully' HERITAGE).
Uses
Specimen or small groupings for lawns, parks and commercial properties, and, in particular, for wet soils along ponds, streams or in low spots. Good choice for the St. Louis area and generally a good substitute for the paper birch in the hot and humid areas of USDA Zones 5-9.