I’m always amazed at the number of people I know who don’t ever prune their perennial plants and trees, preferring the more “natural look” instead. While I can certainly understand their reasoning, the whole point of pruning in the first place is maintain the health and strength of a plant or tree. By not pruning, a gardener sets himself up for some disappointments which are often attributed to the dreaded “black thumb.” So why is pruning important? Let me explain why:
Why we prune
1. Safety. Limbs that hang over sidewalks, fences, or driveways are at risk for falling and damaging property or injuring people. Overhanging limbs can also damage a roof through rot, increase the risk of fire, or damage power and utility lines, costs that you as the property owner could be responsible for. Equally important, pruning reduces the size of overgrown shrubs or gangly tree limbs that block gateways, or restrict vision in the sidewalks and “clear vision triangle” of an intersection. Blocked vision increases the risk of traffic and pedestrian accidents.
2. Health. Even healthy trees and shrubs develop areas of rot, pest infestation, or even inexplicable areas of dead wood. Removing these diseased or dead limbs prevents the spread of disease in the plant and results in cleaner wound closure. Pruning can also improve air circulation and increase exposure to sunlight which results in a stronger tree or shrub.
3. Production. Fruit trees are pruned to encourage fruit growth and increased yields. Without pruning, most of the tree’s energy goes into growth, resulting in a much smaller fruit yield. Flowering shrubs such as roses bloom more profusely when pruned.
4. Keeps fruit trees to a pickable size. Pruning is what keeps semi-dwarf fruits trees to a manageable size, and prevents a cherry or apricot tree reaching heights of 25 feet which are impossible to harvest on an 8 foot step ladder.
5. Aesthetics. For those gardeners who like formal gardens, pruning is a nice way to add some interesting shapes to the yard. Neatly pruned arborvitae for example, look much nicer than arbs that are allowed to grow every which ever. Pruning is also how a gardener creates a topiary, an espalier along a fence, or a shrub in the shape of a giraffe.
6. Compensates for root loss. When transplanting a shrub or small tree, a certain amount of root is always damaged in the process. Pruning back the plant helps stimulate new root growth. While most trees and shrubs should be pruned back just to match up with the amount of root loss, plants likes roses should be pruned back to about 18-24 inches of cane.
7. Pruning avoids weak tree crotches and dual leaders. Most fruit trees come as “whips” which are tall and slender with two to four upright branches that form a broomlike shape. Proper pruning avoids weak crotches which often split in a storm, and instead limits the tree to a single leader.
Strength, safety, health and production are all the reasons why pruning is so important for the health of your plants. For more information about how to prune, visit your local nursery, county extension agent, or the links listed below.