Kenai Birch Betula papyrifera

Betula is Latin for birch and describes a genus of about 60 species of deciduous trees and shrubs found in many gardens and landscapes throughout the northern hemisphere. Betula papyrifera, or Paper Birch, is a loosely pyramidal tree when young changing to irregular oval to rounded with age: It usually retains low branches and can be single or multi-stemmed. It can be trained to be multi-trunked (which tends to produce a shorter tree with an irregular crown) or single trunked (which is taller with a rounded crown). It is easy to transplant and casts a light shade. This tree is noted for its white bark, which exfoliates in papery strips to reveal an orange-brown inner bark. Mature trees develop black markings on the white bark. However, it is not pollution tolerant, has shallow roots, and tends to be short-lived in warmer climates.

Paper Birch is best grown in moist, acidic, sandy or rocky, well-drained soils, but will tolerate a range of soil types. It does well in full sun to part shade, but best foliage color occurs in full sun. If the plant is sited in an area of summer heat and humidity, it will appreciate afternoon partial shade. The plant does best in cool northern climates where summer temperatures rarely exceed 75 degrees F. and where root zones are generally covered with snow throughout the winter. Its native habitat is northern Canada and Alaska and it is the state tree of New Hampshire. Keep the tree consistently moist and consider using soaker hoses and bark mulches to keep the root zones cool and moist. It needs little pruning, but if necessary, you can prune during the dormant season. Do not prune in winter or spring when the sap is running because it will bleed.

Birches are considered a "pioneer" species and, thus, tends to grow quickly when young. Tiny monoecious (male and female) flowers appear in early spring in separate catkins on the same tree. Greenish female flowers are followed by drooping cone-like fruits containing numerous small winged seeds that typically mature in late summer.

Diseases, Insects, and Other Plant Problems:

Birches can become stressed by summer heat and humidity. It is not recommended for planting south of USDA Zone 7. Paper Birch is somewhat susceptible to the bronze birch borer, which can infect and kill trees. Aphids, leaf miner and birch skeletonizer may occur. Watch for leaf spot problems.

VIDEO created by Grant L. Thompson for “Trees, Shrubs, and Woody Vines for Landscaping” a plant identification course offered by the Department of Horticulture at Iowa State University.