Rejuvenation pruning is the cutting back of all stems to a height of 4-10". This technique is used to revitalize leggy, overgrown or diseased shrubs. It is particularly appropriate on the following shrubs:
- Dwarf Bushhoneysuckle (Diervilla)
- Hydrangea -Annabelle
- Spirea (Except Bridalwreath and Snowmound)
Some shrubs dieback to the ground each winter. Remove all above ground foliage from these plants:
- Butterfly Bush
Renewal pruning is the annual or semiannual removal of a shrub's older stems to ground level. This exposes the more productive young stems to full sunlight, while controlling the plant's ultimate height.
To begin, first determine the natural look or growth habit of the shrub to be pruned. Then, determine the age of the stems and remove the older or damaged limbs. Place your loppers as low as possible on each limb and cut. Remove all of the older stems possible without damaging the plant or causing it to look out of balance.
Renewal pruning not only removes older limbs but also lowers the shrub's height. When this pruning method is used along with the "heading back" pruning technique, the shrub size can be drastically reduced without destroying the natural appearance.
After renewal pruning, the remaining branches may be too tall and limber. Head back by cutting at the nearest limb to the desired height. Cut as near to the side branch as possible and at the same angle as the limb.
Tips On Pruning Hedges
Prune hedges wider at the bottom than at the top. This allows light to fall directly onto the lower foliage, keeping it actively growing and replacing the lower leaves.
New growth starts at or near the cuts and forms a solid cover of new foliage. Each time you shear a hedge, leave 1/2-1" of previous growth; the shrub needs this new growth to keep the plant healthy with the ability for regrowth.
Spring Flowering Shrubs and Ornamental Trees
Prune the following shrubs as soon as flowers fade, before new growth starts. Do not prune in winter or before shrub blooms in the spring, as this will remove flower buds that would produce this year's flowers!
Summer Flowering Shrubs
Prune in the dormant season, late winter to early spring, before new growth begins. Pruning after growth starts removes flower buds which would form this year's blooms!
Proper pruning enhances the beauty and natural form and benefits the health of trees. Consider the limitations of the planting site and select trees with the right size and shape.
Pruning Young Shade and Ornamental Trees
Your trees were pruned while growing in the nursery. Limit your pruning as much as possible on a newly transplanted tree because the foliage helps to photosynthesize food necessary for the tree's growth. After your tree is established, the pruning you do should take into consideration the natural growth habit of your tree. Start pruning when the tree is developing its crown and you will be rewarded with a healthy, attractive tree.
Branches that should be removed from trees:
- Eliminate double leader.
- Remove dead or dying branches.
- Remove crossing branches that are rubbing and damaging bark. Open wounds attract insects and diseases.
- Remove water sprouts (strongly upward growing branches common on flowering Crabapples), and suckers (vigorous shoots that originate at the base of the trunk, from the roots.)
Dormancy is the preferred time to prune most trees. Prune Oak, Honeylocust, and Elm while dormant to reduce risk of disease. Other trees can be pruned throughout the year except during leaf out or at time of leaf drop. A few types of trees, notably Maples and Birch, are termed bleeders. If pruned in spring, bleeders produce a great deal of sap. This loss of sap is not harmful to the tree but detracts from the appearance of the tree. To reduce water sprouts, it is best to wait until the Crabapples have leafed out. If water sprouts are removed at this time, less energy is available to the tree for regrowth of new sprouts.
Do NOT Top Trees
"The worst possible thing you can do to your tree is to top it. While this may cause a lot of lush sucker growth to form, topping introduces massive decay, root death, weak and hazardous branches, and greatly shortens the life of the trees .
- Dr. Robert Miller, UW-Stevens Point
To a worker with a saw, topping a tree is much easier than applying the skill and judgement of good pruning. Therefore, topping may cost less in the short run. However, the true costs of topping are hidden. These include: reduced property value, the expense of removal and replacement if the tree dies, the loss of other trees and shrubs if they succumb to changed light conditions, the risk of liability from weakened branches and increased future maintenance. Consult a certified arborist to determine an acceptable method of reducing crown sizes of large trees.
No Flush Cuts
Sometimes larger branches must be removed from mature trees. Branches up to 4-5 inches can be removed but call in a certified arborist if the limb in question is especially heavy, too high, or hanging over electrical wires, a building, or a fence that could be damaged when it falls.
When sawing branches off of trees, "undercut" the branch first at least 4 inches from the trunk to prevent tearing the bark and leaving a large wound on the tree. Then make a top cut all the way through the branch a few inches outside the first cut. The weight of the limb is then removed with the second cut. The final cut should be made from point A to point B to preserve the branch bark ridge and the branch collar, which speeds healing of the wound. The branch ridge and collar area are made of cells that store natural chemicals that prevent decay. Cutting the limb flush with the trunk, once a common practice, removes the collar and prevents proper healing. On the other hand, take care not to leave a stub beyond the collar because it won't heal properly either. The short protrusion that does remain after a proper cut will callus over and become less noticeable as the trunk grows. Wound dressings are no longer recommended except when pruning oaks in an emergency during April 15-September 15. The pruning paint deters picnic beetles which are capable of spreading oak wilt to wounded oaks during leaf out. Prune safely. If you are not confident of doing the work safely, contact a professional arborist or your Bruce Company representative.
In June, head back individual branches of Junipers, Yews, Arborvitae, and Hemlock to create an informal effect and allow them to retain their natural habit of growth. All four evergreens can be sheared into a formal hedge if preferred.
The new shoots of Pine, Fir and Spruce can be pruned back halfway to reduce annual growth, which results in a bushier appearance.
Prune pines in late spring by removing one half of the "candle" or new shoot. Do not damage needle tips, as the tips of cut needles tend to turn brown.
To reduce open spaces on spruces, cut off one half of the leader, or terminal shoot, in the spring when the new needles are about half developed.
If a tree develops two leaders, remove the less desirable one in early spring. Trees with more than one leader are weaker and less attractive than trees that have a single, strong, central leader.
You can replace a lost leader by tying one of the branches in the top whorl to a vertical brace.
Tools for Pruning
Proper tools minimize injury to the plant while encouraging rapid callus formation. These tools include: hand pruner, lopping pruner, pruning saw, pruning pole saw and hedge shears.
The most frequently used tool is the scissors action hand pruner, a tool desirable for removal of limbs and suckers up to 1/2" diameter. Cutting branches or limbs over 1/2" diameter makes the job more difficult and results in excessive damage to the plant.
Lopping shears are useful for pruning branches over 1/2" in diameter. The design of the lopper and the length of the handle determine the leverage and, therefore, how easily the job can be done.
Limbs over 1" in diameter are best pruned with a pruning saw. It is not recommended that one climb trees or prune from a ladder unless absolutely necessary. Pole saws make the job safe and easy from the ground.
Hedge shears, both powered and manual, are designed for creating large, flat foliage surfaces.
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