34 



Commercial Gardening 



variety, pendula. The commoner kinds of Poplar are raised from seeds, 

 but special varieties are usually grafted. 



Prunus (PLUM). There are several species of flowering or ornamental 

 Plums (as distinct from the fruit-bearing kinds), and a good trade is 

 done in them. The Cherry or Myrobalan Plum (P. cerasifera), from the 

 Caucasus, produces its white flowers in April, and is largely used for 

 hedge purposes. The purple-leaved variety, atropurpurea (or Pissardi), 

 is extensively grown, and sprays of foliage are largely used for decorative 

 purposes by florists, &c. The Blackthorn or Sloe (P. spinosa) of the 

 hedges has yielded a purple-leaved form and also one with beautiful 

 double flowers. The finest-flowering Plum, however, 

 is the double-flowered P. triloba, from China, which 

 produces its masses of rose-tinted white flowers in 

 great profusion at the end of March and early in 

 April. The single-flowered type (fig. 431), with rose- 

 white flowers, has been introduced of late years. The 

 Plums flourish in good loamy soil, and are usually 

 budded or grafted on common Plum stocks or 

 layered. (See also "Cerasus", " Amygdalus ".) 



Ptelea trifoliata (Hop TREE). An ornamental 

 North American tree or shrub, 10-15 ft. high, with 

 trifoliate leaves, and clusters of small greenish-white 

 flowers followed by winged hop-like seed pods. The 

 variety aurea has golden young foliage. Loamy 

 soil. Raised from seeds, layers, or cuttings. 



Pyrus. This genus not only includes the Apple, 

 Pear, Quince, and Medlar, but also several fine orna- 

 mental flowering trees and shrubs. The North 

 American Chokeberry (P. arbutifolia) (fig. 432) 

 grows about 10 ft. high, and has oblong leaves, 

 woolly beneath, and white flowers. The White 

 Beam Tree (P. Aria), 40 ft. high, is a native of 

 Britain, with variable and coarsely toothed divided leaves, whitish-woolly 

 beneath, and loose corymbs of white flowers. The British Mountain Ash 

 or Rowan Tree (P. Aucuparia) is one of the most largely grown. It 

 grows up to 30 ft. high, and has ornamental pinnate leaves, creamy-white 

 flowers, succeeded by masses of bright orange -red berry -like fruits in 

 autumn. There are several varieties, like asplenifolia, with leaflets deeply 

 cut] 'aurea, golden-tinted foliage; fructu-lutea, yellow fruited; pendula, 

 drooping; and variegata, with silvery-marked leaves. P. americana seems 

 to be a geographical form. 



One of the most ornamental kinds is P. floribunda (a variety of 

 P. Malus), with pale rose-red flowers, which assume brilliant crimson 

 tints in the variety atrosanguinea. The double- flowered form (flore- 

 pleno or Parkmanni) is a good plant, as are Elise Rathke, Niedzwetzkiana, 

 and Schiedeckeri. 



Fig. 431. Prunus triloba 



