PLUMS 1ST RELATION" TO PRUNING 5 
Trees which make an erect growth often produce numerous long, 
stout, new shoots and a compact top and require thinning out of 
branches at pruning time to admit light to the interior of the tree. 
If the seasonal growth of shoots is short on varieties inclined to 
make a vigorous growth, yearly cutting back at pruning time is usu- 
ally required to induce the production of large fruit. This is more 
especially true if the season's growing conditions are somewhat un- 
favorable or where the plantings are in a location unsuited to the 
variety. If the trees grow well and are naturally spreading or open, 
a pruning practice is needed which will insure strong branches to 
carry the load of fruit as well as to insure fruit of large size. Be- 
tween the decidedly upright and the typically spreading trees men- 
tioned there are intermediate types representing both the triflora 
(Prunus salicina) or Japanese group and the domestica or European 
group. 
Of the varieties which are naturally upright in growth, the Santa 
Rosa and Wickson are examples of the Japanese group and Giant, 
Pond, and Sergeant of the domestica. Left unpruned or pruned but 
lightly, bearing trees of these varieties will assume a spreading posi- 
tion, because of the relatively slender growth of the new wood and 
the weight of fruit. Upright-growing trees of the domestica group 
are much more easily trained to the desired open shapes than are 
those of the triflora, as their branches are inclined to grow at a wider 
angle. With some of the domestica varieties many of the smaller 
fruiting branches and twigs are slender and hang from the larger 
branches after they have been brought to this position by a load of 
fruit. The Giant, Diamond, German Prune, and Lincoln illustrate 
this type as contrasted with trees with stouter fruiting wood, such as 
the Clyman, Sergeant, Imperial Epineuse, and President. Burbank 
of the Japanese group, Climax and Apple of the American-Japanese 
hybrid group, and California Blue, Heine Claude, and Peach of the 
domestica group are examples of varieties which are naturally open 
and spreading rather than drooping. These varieties represent ex- 
tremes in habits relative to the form of tree. Most varieties are 
between them in natural form. 
The round-topped, open tree of moderate growth is the most de- 
sirable from the standpoint of convenience in cultivation, pruning, 
and spraying, for productiveness, and for strength required to carry 
a heavy load of fruit. Most varieties deviate somewhat from the 
ideal in their natural growth, but a satisfactory form may be ap- 
proached by training the young tree. With the more extreme types, 
however, the ideal form may be only approximately maintained and 
this only by a careful and persistent selection of branches when 
pruning. The Jefferson, a variety inclined to make but little wood 
growth, and the Santa Rosa, one which grows vigorously, are examples 
of two of these types. The removal of enough wood at any one 
pruning to cause a radical change in the form of the tree will stimu- 
late a rampant growth and make much subsequent reshaping of the 
tree necessary. This rank growth of new wood of undesirable form 
resulting from severe pruning is more apparent with trees which 
make an erect, compact growth, as does the Santa Rosa, than with 
those which are naturally spreading, like the Burbank. 
