286 PRINCIPLES OF GARDENING. [CH. VIII. 



however young and vigorous they were when first 

 planted. 



How inductive of this disease is a wet retentive 

 subsoil, if the roots penetrate it, appears from the 

 statement of Mr. Watts, gardener to R. G. Rus- 

 sell, Esq., of Chequer's Court, in Bucldughamshire. 

 A border beneath a south wall had a soil three feet 

 and a half in depth, apparently of the most fertile 

 staple, twice re-made imder the du'ection of the 

 late Mr. Lee, of the Vineyard, Hammersmith. In 

 this the trees, peaches and nectarines, flourish for the 

 next three or four years after they are planted, but ai'e 

 then rapidly destroyed by the canker and gum. The 

 subsoil is a stiff sour clay, nearly approaching to a 

 brick eaith ; and the disease occm-s as soon as it is 

 reached by the roots of the trees ^. Mr. Forsyth 

 concluded that the soil is not always the soui'ce of 

 the disease, because it universally and invariably 

 appears at first in the branches, and proceeds thence 

 towards the roots of the tree. But this is certainly 

 not a conclusion waiTanted by the premises, because 

 the acridity of the sap, whatever may be its soirrce, 

 would be likely to injiu'e and corrode, in the first 

 instance, those parts where the vessels are the most 

 weak and tender ; now these, past dispute, are in the 

 branches. Moreover, we generally see the youngest 

 branches the earliest sufferers. 



" Grardener's Magazine, vi. 617. 



