Over pruning reduces the foliage needed to make food for the tree, so in effect, it starves it. When a tree has been over pruned, you may not see much new growth during the spring. In the winter, more branches than usual will break as a result of heavy loads.
Although over pruned trees and shrubs don't usually die if some part of the canopy remains, the damage from over pruning can be extensive. Over pruning reduces the foliage that's available for making food for the rest of the plant and can allow pests and diseases access to the tree if cuts are made incorrectly.
How to Fix an Over-Pruned Tree or Shrub. While some plants need a heftier prune than others, in general, the golden rule is to trim no more than 15 to 20 percent of a tree's canopy at one time. Keep that in mind for next time.
An improper cut like a flush cut (cutting too close to the trunk) or a stub cut (cutting too far from the trunk) can cause irreversible damage to a tree. A flush cut removes the branch collar and leaves a large wound in the side of the tree that won't heal properly.
Pruning during the growing season always stimulates new growth. During summer's heat, having to produce that ill-timed new flush of growth greatly stresses a tree. Pruning in the fall is even worse as it prevents the tree from going into a natural dormancy. The exception is heavily damaged, disease or dead wood.
For a tree to completely compartmentalize and seal off the exterior of a severed branch, it may take upwards of 15 to 20 years. However, within the tree, this containment process is fast-paced and extremely effective.
What is improper pruning? Cutting too close to the nodes or too far from the trunk is referred to as improper pruning. It can cause irreversible damage to your plants. What types of pruning are often done? Thinning cuts, reduction cuts, and heading cuts are often done to prune a plant.
When a tree has been over pruned, you may not see much new growth during the spring. In the winter, more branches than usual will break as a result of heavy loads. Lack of foliage and large numbers of wounds will make your tree vulnerable to pests and disease.
ALWAYS prune back to or just above a growing point (branch or bud) or to the soil line. NEVER leave a stem or branch stub. NEVER top a tree to “rejuvenate” growth.
Pruning Too Aggressively
Yes, it can be fun to prune, but unless you're turning your hydrangea or crepe myrtle into a topiary, don't overdo it. Over-pruning can permanently damage a plant, stunt its growth, and make it susceptible to disease.
Watering is very important during the couple of weeks or more that a plant is recovering from root pruning. Right after pruning, I give the whole pot a thorough soaking. As new growth begins, I make sure to thoroughly wet all the soil at each watering.
Damage caused by pruning
When improperly performed, pruning can harm the tree's health, stability, and appearance. Several consequences occur when pruning is not performed at all. These include development of low aggressive limbs, weak codominant stems, bark inclusions, and accumulation of dead branches.
The solution is to wait until winter and prune again using thinning cuts or reduction cuts. The former takes out an entire branch at its point of origin on the trunk, while the latter cuts a branch back to a lateral branch.
If you need to drastically reduce the size of a shrub or tree, it's often best to look at it as a long-term project, cutting off no more than a third at one time and giving it plenty of time to recover between pruning sessions.
The General Pruning Timeline for Healthy Trees
But in general, most arborists will suggest the following: Mature Trees—Should be pruned or trimmed every 3-5 years. Juvenile Trees—Should be pruned or trimmed every 2-3 years.
Don't prune too late in northern regions.
In areas with cold winters, avoid pruning after the middle of August. If you prune too late, you may stimulate new growth that would not have time to grow thick, protective bark before the killing frosts of winter.
The 1/3 rule involves cutting about 1/3 of wood during any pruning activity. This moderate pruning practice is a balanced approach to thinning out shrubs to stimulate new growth. The plant loses a good amount of stems, usually on the top section, allowing more light and air to enter the inside of the plant.
Differences Between Pruning and Trimming
Webb said pruning typically involves removing dead or diseased wood and thinning out stems and branches to improve the overall health and appearance of a plant. On the other hand, trimming typically involves cutting back plant material for reasons other than health concerns.
Stressed shrubs are more susceptible to disease and pests plus, when cut back too frequently, the shrub may become too weak to fully recover.
The hard pruning approach involves cutting the entire plant down to around 3 to 6 inches from the ground in very early spring before any foliage is emerging. This timing will minimize stress on the plant and direct energy into the growth of new stems.
Don't cut off leaf and flower buds.
Fall pruning may remove the leaf and flower buds that a tree has already set during summer growth.
Can tree branches grow back? When pruned properly, removed tree branches will not grow back. Instead, the tree will grow what looks like a callous over the pruning cut, which helps protect the tree from decay and infection. Because trees heal all on their own, you don't have to use a pruning sealer!
After a tree is topped, it grows back rapidly in an attempt to replace its missing leaves. Leaves are needed to manufacture food for the tree. Without new leaves, the tree will die. The new branches that sprout up below the cuts will continue to grow quickly until they reach the same size it was before it was topped.
April, May and June are not good months to prune because deciduous trees need to use their stored energy to produce new leaves instead of healing wounds. Also, pruning during warmer spring months encourages the spread of diseases such as Oak Wilt and damage by pests such as Emerald Ash Borer.
Young trees should be inspected and trimmed every 1-5 years. Mature trees may benefit from a yearly inspection with perhaps a five- to 10-year cycle of trimming and pruning. Fruit trees may need to be trimmed annually. Hire a qualified arborist to trim trees.