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.
RULE 1: Prune your block with the weakest trees first and your strongest trees last. Trees that are pruned in early winter become more vigorous than trees that have been pruned just before or after flowering.
Municipalities and homeowners often remove the lower limbs for pedestrian and vehicular clearance or to let the sun shine in for grass to grow. Mature trees, especially evergreens, benefit when healthy lower branches are left intact. Removing large limbs can increase the risk of decay.
A good rule of thumb is to maintain at least half the foliage on branches arising in the lower 2/3 of the tree. Pruning of newly planted trees should be limited to corrective pruning. Remove torn or broken branches, and save other pruning measures for the second or third year.
When is the Best Time of Year to Prune Trees? There is never a bad time to remove dead, damaged or diseased branches. But most trees benefit from pruning in mid to late winter. Pruning during dormancy encourages new growth as soon as the weather begins to warm.
The 1/3 pruning rule is a useful guideline when it comes to giving established shrubs and small trees a trim. The notion is that no more than one-third of healthy growth should be removed at one time – whether that's removing one-out-of-three older stems completely, or cutting back each stem or branch by a third.
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.
Not using the proper techniques can damage the health of your tree and can even lead to disease or premature death. In general, don't cut too close to the trunk. These cuts are too big and can delay the sealing of the wound. Don't cut too far from the surface of the trunk, either.
If a tree repeatedly loses too much of its canopy at one time, it can become weak or even die from the stress. That's why you shouldn't trim more than 25% of a tree's canopy at one time. Cutting the branch collar can also be a nasty error.
The best rule of thumb to use when making pruning decisions is to know that you can safely remove up to one-third of the plant's growth at any one time.
According to Ramsey County Master Gardener Volunteers, February is the best time to prune your trees. In February, harmful tree diseases are at a minimum and deciduous trees have already “hardened off”, meaning they have prepared for winter dormancy.
If you cut them too early, you'll cut off the buds that would've opened this spring! The best time to prune spring-blooming shrubs is right after the spring blooms fade.
Branches that Double-cross or Grow Inward or Grow Downward:
Similarly, branches that grow inward toward the central stem or trunk are likely to end up chafing against other parts of the plant, so it's best to prune them.
The node is where leaves, buds and shoots emerge from the stem. You should always cut just above a node, as this prevents 'die back' and therefore disease. Also, by cutting above a node you can manipulate new stems, leaves or flowers to form in a desired direction, as nodes form on different sides of a stem.
While there are many benefits to pruning trees during their dormant periods, you can prune trees once they have buds or leaves — though it's still best to do this while they are dormant.
Although the accepted knowledge is that plants don't have neurons or brains, it's clear that even without nervous systems, trees on some level know what's happening and even feel something akin to pain: when one is cut, it sends out electrical signals and healing compounds — similar to wounded human tissue.
A crown lift is the pruning technique of removing lower branches on a mature tree which lifts the canopy or crown of the tree. It's a really simple technique that is woefully underused in tree pruning.
Some have learned that pruning wounds should be sealed with a pruning compound to “protect” the plant from insects and pathogens. However, scien- tific research tells us that pruning compounds and sealants actually do more harm than good when applied to plants (with one exception which I will mention later).
The basics of hard pruning
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.
In pruning, there are three primary types of pruning cuts, thinning cuts, reduction cuts, and heading cuts, each giving different results in growth and appearance.
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.
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.
Cut too much and you'll risk nutritional deficiencies or branches that are too weak to tolerate the wind or fend off diseases or insect invasions. Over pruning and topping can permanently disfigure your trees, or even kill them. Further, a tree's foliage is important for protecting it against excessive sun exposure.