“Pruning is a necessary part of any fruit operation and nursery businesses,” says Robert Spencer, commercial horticulture specialist at the Alberta Ag-Info Centre. “It is an important tool that helps trees and shrubs develop into properly shaped plants and to maintain healthy and productive plant growth.”
Pruning causes a number of changes, including physical and physiological, in the plant. These changes can affect the entire plant - dwarfing, fruit production, growth habit - or localized points on the plant, such as branch growth direction.
“The effect of specific pruning practices will vary depending on the plant’s age and maturity,” he explains. “For example, 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 it had between the formerly large top and correspondingly large root system.”
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.
Spencer says that in general, early pruning of juvenile plants will:
- Help new plants become well-established. By controlling early top growth, pruning allows the plant to establish a sturdy root system, with top and root growth balanced.
- Helps establish correct plant structure by training growth and by controlling the height, size and shape of the plant.
- Improve plant structure and branching habit, creating a framework for maximized productivity that is compatible with mechanical harvesting. Good structure will also help to reduce mechanical injury and damage.
He adds that as plants and orchards get older, pruning of mature/maturing fruiting plants will:
- Remove sucker growth, which affects row width, airflow within the canopy, etc. In general, pruning keeps the canopy open, improving plant health. Pruning suckers will also keep the row at a desired density, allowing mechanical harvesters to function effectively and efficiently.
- Help maintain plant health and vigorous, steady growth. It does so by keeping most of the plant growth young and healthy and by removing weak, diseased or damaged tissues.
- Encourage the plant to establish new growth regularly, improving plant health and overall vigour. It will ensure that there is a good amount of young, fruiting wood. Pruning will delay plant maturity, in terms of declining productivity, keeping plants young and extending overall orchard longevity. Older plants can be rejuvenated and proper structure and growth habits can be re-established.
- Help keep plants producing a stable and predictable high yield of fruit each year, rather than having a boom and bust biennial bearing cycle.
- Remove diseased, dying or dead plant material to improve health and prolong the lifespan of plants. It can also prevent or limit the spread of problems within an orchard, provided proper practices are followed.
“When properly applied,” he says, “pruning can have a significant impact on the healthy and productivity of individual plants and orchards.