This extremely attractive tree is often planted for its smaller size, speedy growth habit, and striking, white-gray bark, but it also serves as a keystone species, playing a critical role in supporting the food web. It grows 30 to 50 feet tall, usually in a columnar form with multiple slender trunks and an airy crown of shiny, triangular leaves that shimmer golden yellow in fall.
Populifolia references the triangular, poplar-like leaves and Betula is Latin for “birch.” In forests, birch trees thrive on cool, moist, slightly acidic soils. Their very shallow root system makes them sensitive to even short periods of drought, and they tend to grow poorly in hot, dry soils. The best location is one where the soil will be shaded and moist. However, birch trees require full to partial sun on their leaves to grow well. The challenge is to select a growing site where the soil remains cool and moist but the tree receives full sun on its leaves for much of the day. While gray birch has moderate resistance to the bronze birch borer that ruins many non-native birch species, it’s still important to choose an appropriate site so the tree will be as healthy as possible. Excellent locations for placement of birch trees are generally found on the east and north sides of a home where the building provides afternoon shade. Avoid southern and western exposures where the afternoon sun heats and dries the soil. When sited in ideal conditions, gray birch can live up to 75 years old, but its typical lifespan is 30 to 50 years. Sufficient moisture during hot summers is probably the other most important factor in maintaining a healthy birch tree. Mulching with wood chips, shredded bark, and leaf compost will keep the soil cool, retain water, add organic matter as it decomposes, and reduce soil compaction. Young trees should be protected from deer browse.
Gray birch is state-listed as threatened in Ohio and extinct or endangered in several states. It’s the smallest of the northeastern US birches and is sometimes confused with paper birch; however, gray birch’s bark doesn’t peel. Because of its short lifespan, poor shade tolerance, and rapid growth, it's often planted as a pioneer species to repopulate and make way for longer-lived species (other common names are old-field birch and fire birch, which refers to its ability to re-sprout after prairie fires). These attributes also make it a good candidate for home landscapes.
While pruning is not usually needed, those who want to prune should only make cuts September through December because the sap begins to run in late winter and spring. Pruning of birch trees should NOT be done between May 1 and August 1. This is the flight period of the bronze birch borer, and it has been shown that female birch borers are attracted to fresh pruning wounds.
Native habitats include banks of streams, roadsides, woodland edges, sandy woodlands and savannas, and thickets. Use for contrast along woodland edges; space several in a row along paths or driveways; underplant with ferns, native grasses, and woodland plants. It also makes a fine specimen tree.
Plant Characteristics:
Grows 30-50’ tall (up to 75’) and 10-20’ wide. In ideal conditions, may sucker to form a colony.
Prefers full or part sun. Intolerant of full shade.
Prefers well-drained and moist conditions, but tolerates poor, dry soils as well as clay and wet soils. Soils with high pH can cause chlorosis of the foliage.
Male and female catkins appear on same tree late spring to early summer. Solitary male catkins have numerous florets in groups of 3 behind the bracts. Female catkins are erect, consisting of numerous florets in groups of 2-3 behind 3-lobed bracts. Female catkins droop as they mature and are followed by oval-shaped samaras (winged seeds).
Alternate or opposite 3” leaves are deltoid in shape and doubly serrated along the margins. Tips are elongated and gradually tapering. Upper surface is medium green, while lower surface is light green.
Single or multiple trunks are up to 1’ across. Bark is reddish gray when young, turning to white/light gray with horizontal fissures and flattened, black, arrowhead markings from detached branches. Branches are black to gray.
Wildlife Value:
Host for about 400 species of Lepidoptera larvae, including the eastern tiger swallowtail butterfly pictured here with its caterpillar and the lettered habrosyne and birch dagger moths, plus mourning cloak, Compton tortoiseshell, birch dagger moth, and chocolate prominent moth.
Gray birch trees provide food and breeding habitat for numerous species of birds, including hummingbirds, brown creepers, tanagers, vireos, and thrushes. Yellow-bellied sapsuckers drill the trunks for sap, and the slow-dripping sap attracts small insects. Hummingbirds then feed on the insects and the sap. Small, upright cones release seeds in early spring, providing food at a time of scarcity for pileated woodpeckers, black-capped chickadees, songbirds, pine siskins, red squirrels and various other species of birds and small mammals. Young saplings are a favorite browse of deer and rabbits. Beavers and porcupines chew the bark.
Medicinal, Edible, and Other Uses:
Gray birch’s medicinal properties were held in high esteem by Iroquois and other Native American tribes. They made a decoction from the bark for blood purification, skin infections, and as a cathartic. The astringent bark was also used to treat bleeding hemorrhoids.
The trunk can be tapped in early spring before the leaves unfurl to collect birch water that can be reduced to syrup or fermented to make birch beer or vinegar. A refreshing herbal-flavored tea can be made from cold-steeping the inner bark. The leaves are a unique and beautiful addition to salads. The inner bark can be dried and ground into a powder for making cereals or bread.
The wood of this birch is prized because of the ease with which it can be carved, turned, stained, and polished. In the past, it was valued for its ability to regenerate after being cut down. Yellow birch chips can be used to produce ethanol and other products.