Horticulture Principles and Practices

FIGURE 19–23
cordon.
Training and pruning of a
FIGURE 19–24
system.
A four-armed Kniffen training
19.15 COMMON TREE PROBLEMS
As trees and shrubs grow and age, they develop characteristics that reduce their visual
appeal or pose problems in the general environment. Many of these problems can be
corrected by pruning. The major ones include the following:
1. Excessive height. Ornamental trees in open space are normally allowed to grow
freely to attain maximum height. Excessive tree height becomes a problem if it
interferes with utility lines or overwhelms structures such as buildings. When this
happens, the height of the tree may be reduced by drop crotching (cutting a main
branch on the leader back to a lower crotch).
2. Excessive spread. When large branches located high on the tree spread excessively,
they become prone to damage by wind. The condition may also cause the
tree to be deformed and lose its visual appeal. When branches spread excessively,
limbs from the highest and outermost parts should be pruned.
3. Low-hanging limbs. Low-hanging limbs pose clearance problems for humans and
vehicles. It is desirable to establish clearance early in the growth of the plant.
4. Deadwood. When deadwood occurs, it should be removed to prevent disease
infestation and spread. Deadwood also detracts from the beauty of a tree.
5. Overcrowding of trees. As trees grow and mature, they take up more space in the
landscape. That is why it is critical to know the mature characteristics of trees
before installing them in the landscape. Overcrowding can reduce the aesthetic
value of plants considerably. It also causes trees to compete for light and thereby
grow excessively tall. Their natural shapes and forms are often ruined. The
remedy to overcrowding is complete removal of trees or pruning of limbs.
6. Forked trunk. A forked trunk stands the danger of splitting in strong winds to
produce unsightly results. Unless there is an overwhelming advantage to maintaining
two leaders, landscape trees should be trained early to have one trunk and wellspaced
scaffold branches. Only a few (four to six) scaffold branches should be
maintained. All other branches arising directly from the trunk should be removed.
600 Chapter 19 Pruning
19.16 TRAINING AND PRUNING SMALL FRUIT TREES
Small fruit trees may be trained and pruned to be standard sizes, thereby bearing fruits
at a higher level for easy picking. Small fruit trees require some pruning to bear quality,
large fruits and have high yield. Two groups of small fruit trees may be identified in terms
of pruning and training needs—cane and bush fruits.