When a gardener is anxious to get started in the spring garden, a task commonly undertaken is pruning. Most trees and shrubs benefit from annual pruning because pruning has a major influence on a shrub’s flowering habit, shape, size, and pest problems.
A regular pruning schedule protects plants, people, and property from injury, pests and damage. It is an important part of a long-term maintenance strategy.
Pruning removes dead and dying branches and stubs, allowing room for new growth and protecting property and passersby from damage. It also deters pest and animal infestations and promotes the plant’s natural shape and healthy growth.
Pruning trees and shrubs encourages healthy fruit and flower production. Regular trimming develops hedge aesthetics and keeps evergreens proportioned and dense. Such maintenance supports a property’s planned layout and appearance by controlling plant size and shape.
Azaleas can still be pruned without affecting next year’s bloom. Mature azaleas, and other spring bloomers, can be pruned to control shape and remove dead or unproductive branches. (Photo credit: Les Harrison, UF IFAS Extension Agent Emeritus)
Regular pruning reduces the risk of storm damage to structures from broken branches and protects people from falling branches over walkways, driveways, and children’s play areas. This practice also helps control pests and vermin by reducing their habitat options.
Perhaps the most confusing group of plants, when it comes to pruning, is flowering trees and shrubs. Pruning has a major influence on a plant’s flowering.
Over time, an un-pruned flowering plant may become woody, with little new growth to support flower bud development, thus reducing flowering. However, indiscriminate pruning or pruning at the wrong time also may reduce a plant’s flowering.
There is a lot of confusion and many questions about when plants should be pruned. The best answer is that different plants have different requirements.
But, a general rule of thumb is that summer and fall flowering trees and shrubs are pruned in the dormant season (late winter/early spring) and spring flowering trees and shrubs are best pruned soon after their flowers fade.
Spring-flowering shrubs typically bloom on one-year-old wood (twigs that grew new the previous summer). Flower buds develop in midsummer through fall for the following spring.
Pruning in the fall and winter removes flowering wood with buds. Pruning in the early spring (before flowering) also would mean losing some blossoms.
Azaleas (Rhododendron spp.) are an excellent example of a flowering shrub that sets its flowers during the summer and flowers in the early spring. After flowering, the plant will put out a lot of new vegetative growth.
By mid-summer, changes will have begun to occur in the plant buds. Vegetative buds which formerly produced leaves will have changed to reproductive buds capable of forming flowers. Pruning after mid-summer will remove the flower buds destined to open in spring of the following year.
To maximize the next season’s flowers on azaleas and other spring flowering plants, pruning ideally should be done right after the flowering period has ended. Pruning actually may be continued up to about mid-summer, but if it occurs any later, the plant’s flowering potential will be reduced.
However, spring flowering shrubs can be rejuvenated or thinned after mid-summer or in early spring before flowering or growth starts. In this case flowers are sacrificed for growth management.
If flowering shrubs are pruned for rejuvenation, the best time to prune is late winter or early spring. Pruning flowering shrubs at this time will reduce or eliminate blossoming in spring of that year, but the trade-off is in gaining healthier, more vigorous flowering shrubs in the long run.
Hydrangeas (Hydrangea spp.) are an excellent example of a flowering shrub that sets its flowers during the summer. Hydrangea stems bloom only once.
This year’s flowers were formed during summer on last year’s growth. Next year’s flowers will develop on this year’s growth. Pruning back all of the growth on a hydrangea will result in no flowers the next year.
Only those branches which have previously bloomed should be removed. A properly pruned hydrangea leaves one-year old wood which will produce the new flowers.
On spring flowering shrubs which tend to set seed or fruit, roses for example, it is a good idea to ’deadhead’ spent blossoms (remove flowers after they fade). While time-consuming, deadheading conserves the plant’s energy, which would otherwise be spent on fruit and seed development.
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