It’s getting to the end of winter, and most of the orchard pruning will mostly be wrapped up. In case you ever wondered “Why bother?”, I dusted off and reworked something I put together years ago, outlining some of the “Why?” behind pruning.
Why (generally)?
Pruning is a necessary part of any orchard, as well as nursery businesses. It’s also important for privately-owned trees and shrubs. I should emphasize that most of my experience and interest in the pruning of fruiting plants is related to the maintenance of fruiting shrubs, but the principles do apply to the entire spectrum of fruiting plants.
In general, pruning is an important tool in helping trees and shrubs to develop into properly shaped plants. It is part of the ongoing maintenance of healthy and productive plants, which have the capacity to grow and thrive for years. When it comes to fruit trees and shrubs, pruning is a critical tool for controlling and directing plant growth and ensuring that there are good yields over the long life of the orchard.
General Effects of Pruning
Pruning will cause a number of changes in the plant, including physical and physiological effects. These changes can take effect over the entire plant (such as those affecting dwarfing, fruit production and growth habit, etc.) or at localized points on the plant (such as those affecting the growth direction of a branch, etc.). The effect of specific pruning practices depends on the age and maturity of a plant. For example, slight pruning of a newly planted raspberry crown encourages more rooting and reduces moisture stress. Extensive pruning on a large or overgrown orchard will result in a large flush of regrowth, as the plant attempts to re-establish the balance between the formerly large top and correspondingly large root system.
Fruiting Trees and Shrubs
Fruiting trees and shrubs are pruned for a number of different reasons, depending on the age and stage of growth of the individual plant and the entire orchard.
Young Plants
In general, early pruning of (juvenile/immature) plants will help new plants to become well-established. By controlling early top growth, pruning allows the plant to establish a sturdy root system, with top and root growth balanced. It can also help to establish correct plant structure by training growth and by controlling the height, size, and shape of the plant.
Early pruning may improve plant structure and branching habit, creating a framework of branches that is compatible with mechanical harvesting and will result in maximum productivity. Good structure will also help to reduce mechanical injury and damage during harvest.
Older Plants
As plants and orchards get older, pruning of fruiting (mature/maturing) plants removes sucker growth, which affects row width, air flow within the canopy, and other micro-environmental conditions. In general terms, pruning keeps the canopy open, which will improve plant health. Pruning suckers will also keep the row at a desired density, which will allow mechanical harvesters to function effectively and efficiently.
Regular pruning helps to maintain overall plant health. By removing weak, diseased, damaged, dying, or dead plant material will improve health and prolong the lifespan of plants. At the same time, it encourages vigorous, steady growth by keeping most of the plant growth young and healthy. It can also prevent or limit the spread of problems within an orchard, provided proper practices are followed.
Pruning also encourages the plant to continue to establish new growth, which improves plant health and overall plant vigour. This ensures that there is a good amount of young, fruiting wood.
Pruning can delay plant maturity (in terms of declining productivity), essentially keeping plants young and extending the overall longevity of the orchard. Pruning helps to keep plants producing a stable and predictable high yield of fruit each year, rather than having a boom-and-bust biennial bearing cycle.
For plants like raspberries, pruning is more about removing the old spent canes and then thinning the canopy to a point where there is good airflow, minimal rubbing, and mechanical injury. It can also be done to channel/focus the energy of the plant into a smaller number of canes.
Really old stands
If orchards and plants have been neglected and have become overgrown, heavy pruning and/or complete renovation of older stands can rejuvenate the orchard. Once the youth of the orchard is restored, proper structure and growth habits can be re-established.
Conclusions
You might have been asking yourself when you should prune. Many of our trees and shrubs are pruned in the dormant season, prior to when they wake up in the spring. You can also prune dead, diseased, and dying stuff when it is found during the season, if you are careful about it.
When properly applied, pruning can have a significant impact on the healthy and productivity of individual plants and orchards. You can prune a lot or a little, or you can prune regularly or occasionally. Regardless, it is a tool that should be utilized with some frequency, as it is easier to do a little bit of maintenance pruning than have to do massive amounts of restorative pruning.