Common Name: Himalayan birch
Type: Tree
Family: Betulaceae
Native Range: West Himalaya, Nepal
Zone: 5 to 6
Height: 30.00 to 40.00 feet
Spread: 18.00 to 25.00 feet
Bloom Time: April to May
Bloom Description: Yellowish brown (male) and green (female)
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: High
Flower: Showy
Leaf: Good Fall
Other: Winter Interest
Culture
In St. Louis, this birch is best grown in medium to wet, well-drained, sandy or rocky loams in full sun to part shade. Although it prefers full sun in its native habitat, in St. Louis, it is best sited in a northern or eastern exposure that receives some afternoon shade. It needs consistently moist soils. 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 (USDA Zones 5 and 6) where root zones are often covered with snow in the winter.
Noteworthy Characteristics
Betula utilis is native to the Himalayas where it was discovered by Joseph Hooker in 1849. It is a medium sized tree that typically grows to 30-40’ (sometimes to 60-70') tall with an open pyramidal habit. Ovate, double-serrate, yellow-green to green leaves (to 2-3" long) turn golden in fall. Tiny monoecious flowers appear in late spring in separate catkins on the same tree: yellowish-brown male flowers in drooping catkins (to 3-5” long) and greenish female flowers in much smaller, upright catkins (to 1.5” long). Female flowers are followed by drooping cone-like fruits containing numerous small winged seeds that typically mature in early autumn.
Var. jacquemontii is a variety from the western Himalayas (Kashmir to central Nepal) that is most noted for its exceptionally white bark. It is named after French naturalist Victor Jacquemont (1801-1832). Technically the main differences between the variety and the species are that the variety has fewer vein pairs per leaf (7-9 pairs for the variety and 10-14 pairs for the species) and whiter bark. Although bark color can be variable, many authorities consider the bark from this variety to be the whitest found on any birch. Sometimes commonly called white-barked Himalayan birch.
Genus name is the Latin name for birch.
Specific epithet from Latin means useful.
Problems
In the St. Louis area, this birch grows poorly and is generally short-lived. 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. In addition, Japanese beetles may significantly damage the foliage. Although these birches have some susceptibility to aphids, birch leaf miner, birch skeletonizer and dieback, these problems are usually considered to be somewhat minor in comparison to the birch borer. Plants stressed by insects seem more susceptible to cankers.
Uses
Not recommended for the St. Louis climate. River birch is a better selection for St. Louis. In cool northern climates, this white birch is an excellent landscape tree that displays a graceful form and mixes well with evergreens.