Size of the Multi-stem River Birch

Growth and Size

• When grown under high-moisture conditions, multi-stem river birch trees promise fast growth with little care. Individual trees vary significantly in their growth rate for both height and diameter of stems. But when mature, they can reach 100 feet tall with trunks measuring 2 feet in diameter or more. The only North American native birch found in abundance in the hot, humid Southeast, their mature size diminishes in northern zones. Heights of 60 to 80 feet with spreads of 40 feet are more common. Multi-stem river birch trees grown on moist soils live longer, with healthy trees living 50 to 75 years.

Optimal Culture

• For maximum health and size, proper location and soil conditions are essential with multi-stem river birch. Relatively trouble free, the trees prefer full sun and high-moisture, fertile, acidic soils. At all stages of life, from seed germination to full maturity, even moderate shade inhibits their growth. Heavier soils that consistently maintain moisture are ideal. Though well adapted to heat and humidity that few birches tolerate, trees languish in dry conditions. Despite high moisture requirements, they don't tolerate extended flooding. Unless old or damaged, multi-stem river birch trees have no serious pests or diseases. They are highly resistant to bronze birch borer that plagues other birches.

Other Features

• In addition to large size and fast growth, multi-stem river birch trees offer much more. When young, their lustrous silvery-gray bark displays shades of pink, reddish-brown, salmon and cinnamon, always patterned with small, dark vertical lines that add to its beauty. As the trees age, the bark darkens and peels in large, curly, paper-like sheets that reveal more colors beneath. Unlike other birch seeds, river birch seeds are borne in late spring and early summer, instead of fall. The dark green foliage carries a silvery underside that creates an attractive bi-color effect as it flutters in the wind. In fall, the leaves turn golden yellow.

Cultivated Varieties

• Several notable multi-stem river birch cultivars exist. The vigorous Heritage river birch (Betula nigra "Cully") grows 40 to 70 feet tall with heavily exfoliating bark. Layers of cinnamon, salmon and brown peel back to creamy white. Heat- and drought-tolerant Dura-Heat (Betula nigra "BNMTF") reaches 30 to 40 feet with pinkish-orange bark exfoliating to creamy white beneath. The dwarf Fox Valley (Betula nigra "Little King") grows just 10 feet tall in most conditions. Its orange-brown bark exfoliates at a young age. All hardy in USDA zones 4 through 9, these cultivars exhibit outstanding resistance to insects and disease.