180 FRUIT-GROWING 



neglected trees and watch the improvement in 

 the size of the crops and the quality of the fruit. 

 Cultivation should stop early enough in the 

 summer to allow the trees to ripen their wood 

 thoroughly before winter. In the latitude of 

 Philadelphia this should be around the middle 

 of July or the first of August, and the orchard 

 should be planted with some cover crop such 

 as rye, wheat, crimson clover, vetch or rape. 

 Little or no fertilizer is needed on either the 

 plum or cherry. We have recently been using 

 small quantities of nitrate of soda on Japanese 

 plums with what we think are good results — 

 this, again, is in line with the close relationship 

 that seems to exist between these fruits and the 

 peaches. Humus in the soil we must have for 

 neither plums nor cherries will succeed in a 

 burned-out clay or loose sand. This is supplied 

 by the cover crops that are turned under each 

 spring — and the turning under should be 

 started early enough that the work can be done 

 with a heavy disk rather than with a plow. 



Plums have a corner on two diseases that do 

 not bother cherries. One of these is black knot, 

 a disease causing blackened swellings on the 

 branches of the European varieties. I have 

 never seen it on Japanese plums and seldom on 

 American sorts. There is but one way to get 

 rid of it and that is to cut and burn the affected 

 portions. In some sections it is such a serious 



