Sorbus - Chequer Tree, Mountain Ash, Rowan Tree, Service Tree, White Beam, Whitebeam
DESCRIPTION: This is a large group or mostly hardy, deciduous trees and shrubs. They are very easily grown and among the most decorative trees for the yard providing an attractive display for more than one season. There are basically two different types of Sorbus. The plants belonging to the first type are commonly known as Whitebeams. They have simple leaves that often have serrated margins and are sometimes lobed. The leaves are ordinarily white or silvery beneath giving them a shimmering look when blown by the breeze. In the autumn, their clusters of brown to red fruits are attractive and their foliage turns vivid colors. S. intermedia (Swedish Whitebeam) is a small to medium-sized tree with a dense, rounded head of branches. The deeply lobed, shiny dark green leaves are 2 to 5 inches long and clothed in white down on the underside. In the spring, compact heads of white flowers are produced; these are followed by bunches of reddish-orange berries. S. vestita (Himalayan Whitebeam) is an attractive, medium-sized tree with 6- to 10-inch green leaves with a silvery-white or buff color beneath. The green fruits are tinged and speckled with brown. The plants of the second type are commonly known as Mountain Ashes. These plants have pinnate leaves, giving them a fern-like appearance; the foliage turns shades of red and yellow in autumn. In the spring, Mountain Ashes produce clusters of cream-colored flowers, which are followed by 5-inch bunches of attractive berries that are usually brilliant red, but may be white, pink, orange, or yellow. There is one disadvantage with this type however - they are susceptible to fireblight. S. alnifolia (Korean Mountain Ash) grows 40 to 50 feet high. Its crown is cone-shaped when young, eventually becoming rounded. This variety is unusual because it has simple, toothed, oval leaves instead of pinnate leaves. In the spring, it bears white blossoms that are followed by clusters of bright orange to red berries. S. koehniana is a small tree or medium-sized shrub. Its leaves consist of 17 to 33, slender, toothed leaflets. Its porcelain white fruits are produced in pendant bunches on red stalks.
POTTING: These plants can be grown in any good, fertile soil that is well drained and slightly acidic. They need full sun but don't like intense heat. They should be watered well and mulched during periods of dry weather. Pruning, if necessary, should be done in early spring or winter.
VARIETIES: S. domestica (Service Tree); S. Aucuparia (European Mountain Ash or Rowan) & var. asplenifolia, beissneri, Cardinal Royal, Edulis, laciniata, rossica, fastigiata, xanthocarpa, moravica, pendula; S. americana (American Mountain Ash); S. decora (Showy Mountain Ash); S. dumosa; S. occidentalis; S. scopulina; S. sitchensis; S. Vilmorinii; S. Aria (Whitebeam) & var. Decaisneana majestica, chrysophylla, salicifolia, lutescens, magnifica; S. intermedia (Swedish Whitebeam) & var. Brouwers; S. torminalis (Wild Service Tree or Chequer Tree); S alnifolia (Korean Mountain Ash); S. caloneura; S. discolor (Snowberry Mountain Ash); S. Folgneri & var. Lemon Drop; S. japonica; S. Chamaemespilus; S. hybrida; S. Koehneana; S. Prattii; S. scalari; S. cashmiriana (Kashmir Mountain Ash); S. Chinese Lace; S. commixta (Japanese Mountain Ash); S. Eastern Promise; S. Ethel's Gold; S. Ghose; S. Golden Wonder; S. harrowiana; S. hostii; S. hupehensis & var. obtusa; S. hybrida 'Gibbsii'; S. insignis; S. Joseph Rock; S. kewensis; S. koehniana; S. latifolia; S. Leonard Messel; S. megalocarpa; S. Pearly King; S. reducta; S. sargentiana (Sargent Mountain Ash); S. Savill Orange; S. scalaris; S. serotina; S. Sheerwater Seedling; S. Sunshine; S. thibetica var. John Mitchell; S. thuringiaca Fastigiata; S. ursina; S. vestita; S. vilmorinii (Vilmorin Mountain Ash); S. wardii; S. White Wax; S. Wilfred Fox; S. Winter Cheer.
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