2822 



PRUNING 



PRUNUS 



Tools. 



A good large-bladed large-handled sharp knife, a 

 narrow and pointed rather fine-toothed saw, and a pair 

 of shears are the essential pruning tools. Many forms 

 of these three primary implements are on the market. 

 In tools that require such incessant use, 

 when the work is in progress, and that 

 meet such resisting obstacles, only the best 

 makes and materials should be secured. 

 The operator must learn by practice how 

 to use them, for even in such simple im- 

 plements as these there is a right way and 

 a wrong way. Fig. 3211 (from Wester), 

 for example, shows an improper way of 

 using shears, cutting at such a long acute 

 angle rather than crosswise or merely 

 oblique as to render the work difficult, 

 leave a long sharp stub, and injure the 

 shears. A good ladder is also necessary for 

 large trees. When the top or head of the 

 tree is low enough, the pointed ladder 

 shown in Fig. 3212 (from Wester, a 

 bamboo ladder used in the Philippines) is 

 one of the best types; it is easily inserted 

 among the branches and it may be rested 

 securely in a crotch. Many other pruning 

 3212. implements are useful for special work, and 

 A good suggestions of these will be found in various 

 ladder for bulletins and in the catalogues of dealers. 

 P DicJdiL 0r ^ ee a ^ ^e dis cu88 i n m Vol. IV, page 

 1950. L. H. B. 



PRUNUS (ancient Latin name of plum). Rosaceae. 

 THE STONE-FRUITS, as PLUM, CHERRY, PEACH, NECTA- 

 RINE, APRICOT, ALMOND. Pink-flowered and white-flow- 

 ered shrubs and trees of wide distribution, grown for 

 fruit, and also for ornamental foliage and flowers. 



All woody plants: Ivs. alternate, simple, usually 

 serrate and more or less gland-bearing: fls. mostly in 

 spring, sometimes preceding the leaves, either solitary 

 or in clusters, perfect, the pistil single (more than 1 

 in abnormal forms) in a cupule or cup (usually desig- 

 nated the calyx-tube), the stamens numerous and 

 perigynous, the petals and calyx-lobes 5: fr. a drupe, 

 usually 1-seeded by the abortion of one of the 2 ovules. 

 (Fig. 3213.) The species are probably 175, mostly in the 

 North Temperate zone, although a number of species 

 are native in the Andean parts of S. Amer. 



The genus as here outlined includes several well- 

 marked groups, some of which are regarded as distinct 

 genera by many authors. In their extreme or typical 

 forms, these subgenera are very distinct, but the group 

 as a whole is well defined and nothing is contributed 

 to clear definition by raising the groups into generic 

 rank, and it is an advantage for easy reference to have 

 all forms treated in one place rather than to scatter 

 them under several different names. A marked group 

 is Padus, with flowers in true racemes; and its ally, 

 Laurocerasus, is also fairly well distinguished. 



Horticulturally, Prunus is one of the most interesting 

 of all genera. It includes important orchard fruits, 

 peaches, plums, cherries, apricots, and almonds. It is 

 also prolific of ornamental subjects, as double-flowered, 

 variegated-leaved, colored-leaved and weeping forms. 

 Most of the cultivated species are hardy in the latitude 

 of Philadelphia and many are hardy in Ontario. All 

 are of easy culture. Nearly all the species are spring- 

 flowering. Only P. Cerasus var. semperflorens, amongst 

 the commoner kinds, blooms as late as midsummer. 

 They are very useful for spring gardens, therefore, 

 where they make great display, but their short season 

 of bloom and the very ordinary foliage of most of them 

 have limited the planting of the ornamental kinds. All 

 members of the genus are easily grown. 



Some of the ornamental species are not grown on 

 their own roots, but are worked on stocks that can be 



grown easily and cheaply and of which seeds can be 

 secured in abundance. The commonest stocks for 

 the ornamental kinds are the plum (P. domestica), 

 peach, and sweet cherry. On the plum are grown the 

 dwarf almonds and the double-flowering and fancy- 

 foliage plums. The Myrobalan plum (P. cerasifera) is 

 sometimes used for the same purpose. Peach stocks 

 may be used for the same species, as a rule; and they 

 are also employed, particularly in the South, for many 

 fruit-bearing plums. The sweet cherry (P. avium) is a 

 good stock for the various kinds of double-flowered, 

 weeping and fancy-leaved cherries. It is an important 

 point in the growing of these grafted prunuses to 

 remove all sprouts from the stock as soon as they 

 appear. This is particularly true of the dwarf almonds, 

 since the stocks are usually stronger-growing species 

 and tend to sucker from the root. 



In North America there has been a remarkable con- 

 temporaneous evolution of fruit-bearing plums from 

 the native species. Several hundred orchard varieties 

 have been described, and the trees are grown commer- 

 cially over a wide range of country in the South, in the 

 Mississippi Valley and on the Plains, in regions in 

 which the common Prunus domestica does not thrive. 

 An interesting group of pubescent-fruited species of 

 the Southwest may have horticultural importance in 

 future. (See S. C. Mason, Journ. Agric. Research, 1913.) 



In Europe and Eurasia, the fruit-bearing cherries and 

 plums had their original development, chiefly from 

 the three species-groups, P. Cerasus, P. avium, and 

 P. domestica. Ornamental forms are incidental or 

 secondary. In North America, the horticultural devel- 

 opment has been chiefly in edible forms of plums. In 

 the Orient farther Asia and the Chino-Japanese 

 region the peach and apricot groups probably had 

 their origin, as well also as the fruit known to us as the 

 Japanese plum; but Japan is noted for its cherries cul- 

 tivated for bloom rather than for fruits. Only the 

 indifferent P. Pseudo-Cerasus, among the cherries, is 

 natively grown for fruit in China and Japan. 



The Japanese flowering cherries are singularly beau- 

 tiful and attractive. They should be better known in 

 this country. A number of forms have been long intro- 

 duced and a few of them are advertised, but apparently 

 they have not been carefully chosen as to hardiness and 

 adaptability. David Fairchild reports that the trunks 

 of the less vigorous forms of his ten-year-old collection 

 in Maryland are sometimes winter-killed, especially on 

 the southwest side, but there are many which, at least 

 in Maryland, are hardy and form good-sized trees. The 



3213. Flowers of plum. The ovary, or young plum, with 

 the ovule inside, is at o. (Natural size.) 



drooping single forms (P. subhirtella var. pendula) are 

 among the hardiest and most showy from a distance, 

 but are surpassed by the wonderful double forms (P. 

 serrulata) which produce great masses of flowers as 

 beautiful and quite as large as many semi-double roses. 

 The question of stock is important. In Europe, nursery- 

 men have generally grafted the Japanese cherry on P. 

 Cerasus and P. avium, as well as on the Mahaleb. Most 

 of the specimens of the pendula varieties commonly seen 

 are grafted high on one of these stocks, but the effect 

 in old specimens is grotesque and the trees are short- 

 lived. The Japanese grafted trees sent to this country 



