|Betula subsp. var.||Silver Birch|
Silver Birch, European Weeping Birch, European White Birch, or Weeping Birch (Betula pendula) is a widespread European birch, though in southern Europe it is only found at higher altitudes. Its range extends into southwest Asia in the mountains of northern Turkey and the Caucasus. The closely related Siberian Silver Birch (B. platyphylla) in northern Asia and Sichuan Birch (B. szechuanica) of central Asia are also treated as varieties of Silver Birch by some botanists, as B. pendula var. platyphylla and B. pendula var. szechuanica respectively (see birch classification).
Betula pendula is a medium deciduous tree, typically reaching 15-25 m tall, exceptionally up to 30 m, with a slender crown of arched branches with drooping branchlets. The bark is white, often with black diamond-shaped marks or larger patches at the base. The shoots are rough with small warts, and hairless, and the leaves 3-6 cm long, triangular with a broad base and pointed tip, and coarsely serrated margins. The flowers are wind-pollinated catkins, produced before the leaves in early spring, the small (1-2 mm) winged seeds ripening in late summer on 3-5 cm long catkins.
It is distinguished from the related Downy Birch (B. pubescens, the other common European birch) in having hairless, warty shoots (hairy, without warts in Downy Birch), and whiter bark often with scattered black fissures (greyer, less fissured, in Downy Birch).
|Standard Cyclopedia of Horticulture|
Betula pendula, Roth (B.verrucosa, Ehrh. B. alba, Linn., in part). Tree, to 60 ft., with slender, in older trees usually pendulous, branches: young branchlets usually glandular: Lvs. rhombic-ovate,¾- 2½ in. long, glutinous is when young, glabrous, usually cuneate, sometimes truncate at the base, acuminate, doubly serrate; petioles slender, about 1 in. long: strobiles cylindric, about 1 in. long, slender-peduncled, usually pendulous: wings of nutlet about one and a half to two and a half times as broad as its body. Eu. to Japan. Var. "Tauschii, Rehd. (B. japonica, Sieb. B. alba var. Tauschii, Shirai. B. pendula var. japonica, Rehd.). Lvs. broadly ovate, truncate or sometimes subcordate at the base, sometimes puberulous beneath and often with tufts of hairs in the axils. Var. dalecarlica, Schneid. (B. laciniata, Wahl. B. hybrida, Blom). Lvs. more or less deeply lobed with irregularly serrate-acuminate lobes: branches on older trees pendulous.—A very graceful tree. Var. fastigiata, Koch (B. alba fastigiata, Carr. B. pendula pyramidalis, Dipp.). With straight upright branches, forming a narrow columnar pyramid. Var. tristis, Schneid. With very slender, strongly pendulous branches, forming a round regular head. Var. Youngii, Schneid. (B. alba pendula Youngii, Moore. B. pendula elegans, Dipp. B. alba elegantissima pendula, Hort.). Branches very slender, strongly pendulous; primary branches spreading or recurved, forming an irregular picturesque head; similar in habit to the weeping beech. Var. gracilis, Rehd. (B.alba laciniata gracilis pendula, Hort. B. elegans laciniata, Hort.). Habit like the preceding, with laciniate Lvs. Much slenderer and smaller and of slower growth than var. dalecarlica. Var. purpurea, Schneid. (B.vulgaris purpurea, Andre. B. alba atropurpurea, Lauche. B. pubescens atropurpurea, Zabel). Lvs. dark purple.
Successful birch cultivation requires a climate cool enough for at least the occasional winter chill. Shallow rooted they require water during dry periods, growing best in full dun or dappled shade. They require deep, moist, fertile soil.
The plant prefers light (sandy), medium (loamy) and heavy (clay) soils, requires well-drained soil and can grow in heavy clay and nutritionally poor soils. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very acid soil. It cannot grow in the shade. It requires dry or moist soil. The plant can tolerates strong winds but not maritime exposure.
A very easily grown plant, it tolerates most soils including poor ones[1, 24], sandy soils and heavy clays. It prefers a well-drained loamy soil in a sunny position[11, 200]. It is occasionally found on calcareous soils in the wild but it generally prefers a pH below 6.5, doing well on acid soils. Fairly wind tolerant though it becomes wind shaped when exposed to strong winds[K]. The silver birch is a very ornamental tree with many named varieties[11, 200]. It also has a very wide range of economic uses. It is a fast growing tree, increasing by up to 1 metre a year, but is short-lived[17, 200]. It is often one of the first trees to colonize open land and it creates a suitable environment for other woodland trees to follow. These trees eventually out-compete and shade out the birch trees[17, 186]. It makes an excellent nurse tree for seedling trees, though its fine branches can cause damage to nearby trees when blown into them by the wind. Trees take about 15 years from seed to produce their own seed. Although closely related, it does not usually hybridize with B. pubescens. It often hybridizes with B. pubescens according to another report. A superb tree for encouraging wildlife, it has 229 associated insect species. A good plant to grow near the compost heap, aiding the fermentation process[14, 20]. It is also a good companion plant, its root action working to improve the soil. Trees are notably susceptible to honey fungus.
Seed - best sown as soon as it is ripe in a light position in a cold frame[78, 80, 113, 134]. Only just cover the seed and place the pot in a sunny position[78, 80, 134]. Spring sown seed should be surface sown in a sunny position in a cold frame[113, 134]. If the germination is poor, raising the temperature by covering the seed with glass can help. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in a cold frame for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. If you have sufficient seed, it can be sown in an outdoor seedbed, either as soon as it is ripe or in the early spring - do not cover the spring sown seed. Grow the plants on in the seedbed for 2 years before planting them out into their permanent positions in the winter[78, 80, 113, 134].
Pests and diseases
- Purpurea has rich dark purple leaves.
- Laciniata (commonly misidentified as Darlecarlica) has deeply incised leaves and weeping branches.
- Tristis ha
s and erect trunk with weeping branchlets.
- Youngii has growth similar to a weeping willow (Salix sp.) with no central leader requiring grafting onto a standard.
- ↑ Botanicas' Trees & Shrubs, Random House, Sydney, 2005
- Plants for a Future - source for some creative commons text
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963