36 PROPAGATION BY GRAFTING. 



fore mid-summer, when the part intended to root is some- 

 what mature and firm in texture. The pear, the apple, and 

 the quince, if layered early in the spring ; or the grape in 

 summer will usually be well rooted in autumn. 



A moist season is the most favorable to the rooting of 

 layers, by preserving a softer bark. For this reason, many 

 plants may be more easily propagated in England than in 

 the United States ; and more readily in Ireland than in 

 England. 



Layering is largely made use of in propagating the grape, 

 occasionally for the quince, and sometimes for the apple. 

 It is also of very extensive application in propagating many 

 ornamental trees and shrubs. 



Suckers may be regarded as spontaneous layers, the new 

 shoots being sent up from buds on the roots or portions of 

 the stem beneath the surface of the ground. They are the 

 only mode of multiplying most species of the raspberry. 

 The runners of strawberries may be regarded as layers or 

 suckers above ground. 



III. GRAFTING. 



Upwards of twenty different modifications of grafting were 

 mentioned by the ancient Roman writer, Varro ; and Thouin, 

 of Paris, has described and figured more than a hundred 

 kinds. The great number of modes described in books, has 

 tended rather to bewilder than to enlighten beginners ; the 

 following remarks, therefore, are more for the purpose ol 

 laying down reasons on which success depends, than foi 

 pointing out the peculiar modes of operation, which may be 

 varied according to convenience, provided attention is given 

 to the essential particulars. 



Propagation by grafting differs mainly and essentially 

 from increasing by cuttings, by inserting the cutting into 

 the growing stock of another tree instead of directly into the 

 soil. The stock thus supplies the sap, as the soil does in 

 the case of a cutting ; and the graft, instead of making roots 

 of its own, extends its forming wood downwards, at the in- 

 ner surface of the bark, into the stock itself. Hence there 

 are two chief requisites for success : the first, that the graft 

 be so set in the stock, that the sap may flow upward with- 

 out interruption; and the second, that the forming wood 



