50 



CASSELL'S POPULAR GAEDENlNa. 



The Shelter of Walls.— TKe higher in reason 

 the wall, the greater its efficacy. But this general 

 principle needs to be modified in practice hy another 

 and an opposite fact, that may be stated thus : — The 

 efficiency of walls as shelters and ameliorators of cli- 

 mate is devised upon the give-and-take principle ; in 

 other words, in so far as the favoured side of the wall 

 is more warm, the shady side becomes colder ; and 

 this principle of reciprocity in the redistribution of 

 caloric acts as a wholesome restraint in moderating 

 the heights of walls. In practice, perhaps, the most 

 useful height of Pear walls for sheltering and foster- 

 ing the trees is twelve feet. Occasionally they are 

 much higher than this — fourteen, sixteen, and even 

 eighteen feet. More frequently they are lower — 

 six, seven, eight, nine, and ten feet being common 

 heights. All these are rather low for developing to 

 the utmost the ameliorating iufluence of walls on 

 local climate, and developing to the full the fruit- 

 ing and growing capacities of healthy Pears. 



The warming power or heating force of walls 

 is often much weakened by covering them too closely 

 with the leaves and branches of trees. Such loose 

 and verdant drapery absorbs and retains but little 

 heat. Bricks, the best of all materials for walls, 

 absorb, retain, and concentrate the solar rays into 

 a sort of focus by day, thus raising the tempera- 

 ture many degrees, and distribute it by night, to 

 counteract the energy of radiation. Each exposed 

 brick, or part of a brick, thus becomes an absorber, 

 storer, and distributor of heat, and the wall, as a 

 raiser of local temperature, is efficient in the ratio 

 of its baldness, or nearly so. 



But, of course, walls are built chiefly to grow Pear 

 or other trees on their surface, and the great practical 

 problem for solution is the striking of a happy mean 

 between the trees and the brick wall, so that the 

 latter shall exert its maximum amount of heating 

 force, and the trees produce as many and as fine 

 Pears as practicable. To combine these two to most 

 advantage, the branches should average about a foot 

 between them, whatever method of training may be 

 adopted. 



There are also walls of dwelling-houses, farm 

 buildings, stables, cart-sheds, carriage-houses, work- 

 shops, factories, and maltings. The latter are espe- 

 pially named, as some of the finest Pear-trees known 

 to the writer are grown on maltings. Magnificent 

 specimens of Maria Louise and other Pears are also 

 grown on the gable-ends and other walls of lofty 

 dwelling-houses. In planting Pears on specially 

 high walls, special preparations should be made for 

 them, and larger areas, nine or twelve feet over, 

 and from four to five feet deep, should be carefully 

 prepared for the trees. 



Pears also do well on wooden fences or espalier 



rails, and may be planted thickly on those to form 

 fruit hedges in genial climes and warm localities. 



The Planting.— Little need be added here to 

 what has already been stated under Apples. Pears, 

 however, may be planted a fortnight or three weeks 

 earlier. 



The distance between Pears need diffei? but little 

 from that of Apples (see Vol. II., p. 251). On high 

 walls, and with vigorous-growing varieties on Pear- 

 roots, the distances between Pears may be extended 

 from twenty to twenty-five, or even thirty feet. In 

 some of the old gardens the giant horizontal-trained 

 Beurres and Bergamots used to be forty feet apart ; 

 for orchard Pear-standards, from thirty to thirty- 

 five feet between the rows, and twenty to thirty 

 feet from plant to plant. But all this refers to Pear- 

 trees on the Pear. The use of Quince stocks, the 

 practice of root-pruning, and the introduction of 

 cordons and other small trees, have wholly revolu- 

 tionised the old ideas of distance, and resulted in 

 what the old Pear-growers would have called an 

 absurd multiplication of roots to areas. They how- 

 ever mostly introduced a tall tree, or rider, between 

 each two dwarfs. In addition to this, it was a com- 

 mon practice to plant twice as many dwarfs at 

 first as were required. >Similar modes of econo- 

 mising space were adopted in orchards. Tem- 

 porary rows of trees, either dwarfs or standards, 

 were planted between the permanent rows, and also 

 between the permanent plants in the rows. By this 

 simple method four times as many trees were grown 

 at the first as were finally left, and the nurses or 

 riders repaid the cost of their purchase and planting 

 many times by their produce, before they were finally 

 cleared ofi to make room for the permanent trees. 



In orchards, again, or Pear gardens, it is customary 

 not only to sub-crop with temporary trees, but with 

 other crops, such as bush-fruits and Strawberries , 

 and as the sub-crop is often almost as valuable as 

 the super one, these under-crops exert a modifying 

 influence on the distances of the Pears. Pears on the 

 Quince and double-grafted Pears, also, should be 

 planted as close again as those on the Pear. From 

 fifteen to twenty feet apart is ample for Pear-trees 

 on walls or espaliers worked on the Quince. It is 

 customary to plant the same trees on espaliers four 

 or five feet closer than on walls; as, of course, the 

 espalier is not so warm, and does not foster growth 

 to the same extent. From seven to ten feet would, 

 therefore, be good distances for Pears on espaliers on 

 the Quince. 



Pyramids vary 30 much in size and character, and 

 rate of growth in different localities, that they may 

 have as wide a range of distance as from five to 

 twenty feet. For semi-weeping pyramids or QueneEe 



