The birch tree belongs to the Betula genus and is most commonly used for ornamental purposes or for timber. There are about 40 varieties of birch around the world, most of which grow in cooler regions in the northern hemisphere. This deciduous tree has a smooth and often flaky bark and leaves that vary in shape from heart-shaped to egg-shaped to triangular and have serrated edges.
Paper birch (Betula papyrifera) is also known as canoe birch because some Native Americans used birch bark in making canoes. It grows 15 to 24 metres / 50 to 80 feet tall and can spread to a width of about 9 metres / 30 feet. Its leaves are egg-shaped with a pointy tip. Paper birch is moderate to fast growing and, as a young tree, has brown bark that becomes whiter and begins to peel as the tree ages. The wood makes excellent firewood, and the sap can be boiled down to produce birch syrup. It grows in USDA Hardiness Zones 2b to 9b.
The yellow birch (Betula alleghaniensis) is slightly smaller than the paper birch, growing to between 15 and 21 metres / 50 and 70 feet tall. The tree gets its name from its yellowish bark that changes to a reddish-brown as it ages. When still immature, the tree's twigs tend to have a bronze twinge of colour. It is a slow-growing birch with oval-shaped leaves with pointed tips. The yellow birch is commonly used for timber and for making furniture. It grows in USDA zones 2a to 9b.
The River birch (Betula nigra) grows along rivers and other wet areas like marshes and ponds. It is also occasionally known as red birch due to its light-red peeling bark. It grows from 12 to 21 metres / 40 to 70 feet in height and can be much wider than other birch varieties, spreading out to 18 metres / 60 feet. The river birch is often used for landscaping and ornamental purposes because of its reddish, salmon peeling bark. It is hardy in USDA zones 4a to 9b.
European white birch
The European white birch (Betula pendula), also known as the silver birch, is a short variety that grows to a maximum of 15 metres / 50 feet in height and can spread to 9 metres / 30 feet. The European white is a fast-growing birch that also has a tendency to be multi-trunked. Unfortunately, while fast-growing it also tends to be short-lived, unless in a northern climate with plenty of moisture. It is also rather susceptible to insect problems, which is why it is not generally used for landscaping or ornamental purposes. It is hardy in USDA zones 3b to 9a.
Crimson Frost Birch
The crimson frost birch (Betula sp. "Crimson Frost") is named for its reddish leaves. It is a hybrid between the Purple Rain birch (Betula pendula "Purple Rain") and the Japanese white birch (Betula platyphylla var. japonica). There are very few "red-leaf" birches around, which is why this variety is commonly requested by landscapers. The leaves are a deep burgundy during the summer and then slowly change to crimson, then orange-yellow in later autumn. The tree grows to a height of about 11 metres / 35 feet and can spread to a diameter of around 6 metres / 20 feet. The crimson frost makes an excellent accent tree. It grows in USDA zones 4a to 7b.