PLUMS IN RELATION TO PRUNING y 
FRUITING HABITS IN RELATION TO GROWTH 
For the purpose of studying fruiting habits of plum trees in 
relation to the portion of the tree on which the fruit is borne, the 
varieties grown commercially are considered under two groups, the 
Japanese and the domestica. 
In the Japanese group, fruit is borne both at nodes on 1-year-old 
wood and on spurs throughout the tree. It is found on spurs with 
leaves or at nodes of 1-year-old wood where spurs are forming, 
except that shaded or crowded spurs sometimes set fruit but fail 
to produce leaves and die after the fruit ripens. Some leafless 
nodes of slender, crowded, 1-year-old twigs also bear fruit. As 
with varieties of the domestica group, little, if any, fruit is borne 
on large 1-year shoots which develop on branches which were headed 
back or on water sprouts lower in the tree. On the 1-year-old wood, 
the crop is often heaviest on the shorter, more slender wood; and 
in many cases the fruit on such wood is not of profitable size and 
market quality unless both fruiting branches and fruit are well 
thinned. 
Many varieties of the domestica group bear much of their fruit at 
leafless nodes of 1-year-old wood. Most of these varieties bear only 
an occasional fruit, if any, at a node where a spur or twig is form- 
ing. The California Blue is one of the exceptions to this. Leafless 
nodes which bear fruit remain barren after the fruit ripens, and 
varieties of the twig-forming type often require new twigs each 
year to provide fruiting wood for the following season. A few 
domestica varieties produce spurs instead of twigs, and with these 
the crop is produced largely on spurs. If for lack of moisture or 
other causes the wood growth on such trees was short the previous 
year, fruit production will often be heavy on the 1-year-old wood, 
as with twig- forming varieties, and be produced almost entirely^ at 
leafless nodes. A short portion of the 1-year-old wood on such trees 
is barren of both fruit and leaves; and as the upper end of the 
branch produces no fruit, there is a proportionately long segment 
which bears fruit at leafless nodes and remains barren thereafter. 
This leaves but a small segment of the twig to produce fruit the 
following season. On such trees, many of the spurs which form are 
short and produce heavily when 1 year old and die after harvest. 
To provide more fruiting wood for such trees, it is necessary to alter 
growing conditions or adopt a pruning method which will induce a 
more vigorous wood growth. 
HABITS OF GROWTH OF FRUIT SPURS 
Fruit spurs of most varieties may be placed in one of two classes : 
(1) Those of the rosette type, or those which are inclined to end in a 
cluster of short, compact branches ; and (2) those inclined to become 
considerably lengthened by the outgrowth of the terminal bud of 
the spur leader. The Burbank, Gaviota, and Duarte furnish illus- 
trations of the former and the Formosa and California Blue of the 
latter (see pi. 5, B; pi. 9, D; pi. 10, C; and pi. 17, D). Most Japa- 
nese sorts and their hybrids fall within the first group, the Formosa 
being a decided exception. In the second class are included many of 
