-10- 



dcvotcd to that crop and little attention has been given to tlic 

 pi uni . 



Tlie discussion that follows is offered as a brief guide to 

 the training and pruning of plum trees. 



Training Young Trees 



There is a marked difference in the growth habit of plum 

 trees depending on type and variety. Some are decidedly up- 

 right while others are distinctly spreading in growth habit. 

 Regardless of growth habit, most are probably best trained as 

 a central or modified central leader tree. 



The plum tree should have 5 or 6 scaffold branches spaced 

 about 6 inches apart and spirally around the leader. On upright 

 growing trees, it would be advisable to spread the branches to 

 improve the trees structure. Excessively long branches should 

 be shortened, preferably by cutting it back to an outward grow- 

 ing lateral. Heading-back cuts may be used when necessary to 

 shorten and/or stiffen the scaffold branches. 



Pruning Bearing Trees 



Flower buds are formed laterally on current seasons growth 

 and on the extension growth of spurs. The flower buds are sim- 

 ple, containing 1 to 3 flowers, but no leaves. The terminal 

 bud of both shoots and spurs are leaf buds. European varieties 

 fruit more heavily from spurs; Japanese types fruit heavily from 

 both shoots and spurs. The shoot of a Japanese plum is similar 

 to the peach in flower bud development. 



Annual pruning helps to maintain a supply of new wood on 

 which the flower buds can form. For the Japanese varieties, an 

 annual shoot growth of 10 to 20 inches for young trees and 10 to 

 12 inches for older bearing trees is desired. European varie- 

 ties should average 9 to 18 inches of annual shoot growth for 

 young trees and 6 to 10 inches for older bearing trees. After a 

 plum tree begins bearing, an annual thinning out of watersprouts 

 and branches growing towards the center of the tree will con- 

 stitute the major part of the pruning operation. The tree should 

 be kept open to allow for good light penetration, air movement 

 and spray coverage. Control of brown rot will be much easier if 

 the tree is prevented from becoming too dense. Keeping the trees 

 open will also maintain fruiting throughout the lower and inner 

 portions of the tree. Some heading-back cuts may be necessary to 

 shorten and/or stiffen the scaffold branches. 



Removal of Black Knots 



The plum is particularly susceptible to the fungus disease, 

 black knot, which may be identified in the dormant season by 



