Betula pendula aka Common Birch

Silver birch, Betula pendula, is a deciduous tree in the birch family. Gardeners also know it as European white birch or warty birch. It grows wild across most of Europe and into western and central Asia. Its range runs from the Caucasus through Siberia to China and Japan. It is native to Britain and Ireland and is the national tree of Finland. In the boreal zone it can dominate whole forests.

In gardens the tree reaches 40 to 60 feet (12 to 18 m) tall and 20 to 40 feet (6 to 12 m) wide. Wild trees can top 80 feet (24 m), and some reach 100 feet (30 m). Young trees have a pyramidal outline. The crown becomes more oval with age. The trunk stays upright, while the slender twigs droop at all ages.

The white bark is the main attraction. On older trunks it develops black vertical fissures. Near the base it turns dark and rugged. Sources disagree on peeling: some describe papery strips, while others say the bark barely exfoliates. Young twigs are brown and warty. The leaves are diamond-shaped to ovate, 1 to 3 inches (2.5 to 7.5 cm) long, with doubly serrate edges and long, tapered tips. Glands dot both leaf surfaces. Foliage turns yellow in autumn and stays on late for a birch, though colour varies from year to year.

Male and female flowers grow in separate catkins on the same tree. They open in early spring, around March to April. The yellowish-brown male catkins hang down and reach 3.5 inches (9 cm). The smaller green female catkins stand upright. They ripen into drooping, cone-like fruits that release many tiny winged seeds in late summer. The flowers have little ornamental value.

Silver birch is very cold hardy, to USDA zone 2 and RHS H7. It prefers cool climates with mild summers and does poorly in heat and humidity. Plant it in full sun or light shade in moist, well-drained soil. It tolerates sand, clay, loam and chalk, and acid or alkaline conditions. Mulch helps keep the roots cool and moist. Prune only in the dormant season. Pruning in late winter or spring makes the cut wood bleed sap. The tree grows fast when young. Use it as a lawn specimen, in small groups, or as a multi-stemmed tree. It casts light shade and looks good beside conifers in winter.

The bronze birch borer is the most serious threat. Silver birch ranks among the birches most prone to it, especially when heat or drought stresses the tree. Aphids, leaf miners, leaf-mining sawflies and birch skeletonizer also attack it. Diseases include honey fungus, rust, powdery mildew and leaf spot. Ice and snow can break branches. The tree drops many small twigs and often lives only 10 to 15 years in warm regions. Deer tend to leave it alone.

People tap the sweet spring sap to drink, boil into syrup or brew into beer. The inner bark has served as a famine food. Tar made from the bark irritates the skin.