Common Name: Asian white birch
Type: Tree
Family: Betulaceae
Zone: 3 to 6
Height: 20.00 to 40.00 feet
Spread: 10.00 to 20.00 feet
Bloom Time: April
Bloom Description: Yellow brown (male), Green (female)
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: High
Suggested Use: Naturalize, Rain Garden
Flower: Showy
Leaf: Good Fall
Other: Winter Interest
Tolerate: Deer
Culture
In St. Louis, gray birch is best grown in medium to wet, well-drained, sandy or rocky loams in full sun to part shade. It seems to tolerate drier soils in its native range. It also tolerates poor soils. In the St. Louis area, it is best sited in a northern or eastern exposure that receives some afternoon shade. Consider using soaker hoses and bark mulches to keep the root zones cool and moist. It needs little pruning, but if necessary, prune during the dormant season. Avoid pruning in spring when the sap is running. Performs best in cool northern climates where summer temperatures rarely exceed 75 degrees F. and where shallow root systems are generally covered with snow throughout the winter. In optimum growing conditions, plants will easily spread by suckers.
Noteworthy Characteristics
Betula populifolia, commonly called gray birch, is a short-lived, narrow-columnar, suckering, deciduous tree that typically grows to 20-40’ tall. It most often appears in a multi-trunked form, but also grows with a single trunk. It is native primarily from Southeastern Canada to Virginia, with a scattering of plants extending westward to Illinois. It typically occurs in both dry and wet soils. This tree is noted for (1) its non-peeling chalky white bark with dark chevron trunk patches appearing below each branch base and (2) its long-pointed triangular green leaves. Triangular leaves (each to 3” long) are double-toothed and shiny with tapered tips. Fall color is usually undistinguished. Tiny monoecious flowers appear in early spring in separate catkins on the same tree: yellowish-brown male flowers in single catkins (to 4” long) at the branch tips and greenish female flowers in smaller, upright catkins (to 1/2” long). Female flowers are followed by drooping cone-like fruits containing numerous small winged seeds that typically mature in late summer. Plants have rough-warty twigs.
Genus name is the Latin name for birch.
Specific epithet come from the Latin populus meaning poplar genus and folia meaning leaves like those of the poplar.Species name comes from Populus (poplar genus) and Latin folia (leaf) in reference to leaf appearance.
'Whitespire' is best known for its upright form, non-exfoliating white bark, dark green leaves and attractive yellow fall color. Vegetatively propagated plants of this cultivar are considered to have better resistance to bronze birch borer than seed propagated plants, resulting in the use of the cultivar name 'Whitespire Senior' by some nurseries as a way of designating those plants which have been vegetatively propagated. 'Whitespire' was originally named as a cultivar of Betula platyphylla var. japonica when introduced into commerce in 1983, but that designation was subsequently changed when it was determined 'Whitespire' was in fact a gray birch.
Problems
This species of birch grows poorly and is generally short-lived in the St. Louis climate. It thrives in cool northern summers, but does poorly in the heat and humidity of St. Louis. Weakened birches become very vulnerable to the bronze birch borer which, in the St. Louis area, typically infects and kills trees that are stressed by summer heat and humidity. This tree reportedly has some resistance to the borer. Birch leaf miner may also cause significant problems. Although this gray birch has some susceptibility to aphids, birch skeletonizer and dieback, these problems are usually considered to be somewhat minor in comparison to the birch borer and birch leaf miner. Plants stressed by insects seem more susceptible to cankers.
'Whitespire' reportedly has some resistance to the borer.
Uses
Not recommended for the St. Louis climate. River birch (see Betula nigra) is a better selection for St. Louis. In cool northern climates, this gray birch may naturalize by self-seeding and root suckers to form attractive strands. It also can be effective as a landscape tree.