Why, When, How to Prune Shrubs and Hedges
There are three major types of pruning aesthetic, productive, and practical.
Aesthetic pruning is done to improve the appearance of a tree or shrub. Most aesthetic pruning is done to create or maintain both symmetry and a desired shape and height. Artistic aesthetic pruning can also be done on hedges and shrubs to create very interesting topiary designs.
Productive pruning is the process of removing non-productive limbs or stems from fruit trees and tomato plants so that more energy goes to the productive parts of the plants. Apple (as well as other fruit) growers rigorously prune their trees for the sole purpose of improving apple production, with no genuine concern for the trees’ aesthetic appeal although the trees look good to other apple growers.
Practical pruning is the process of removing limbs or branches that would otherwise interfere with power lines, walkways, decks, or other structures. We also consider the removal of interfering limbs and branches as “practical pruning” because such preventive measures often improve the tree’s or shrub’s health and help prevent damage.
When to Prune
Most pruning is done in the spring and early summer, as virtually all pruning encourages new growth. Fruit and ornamental trees are easiest to prune before they start to generate the new season’s leaves it’s easier to see the overall shape of the tree, and clean-up is a lot easier, too. Most hedge trimming is done shortly after new growth starts to appear.
Fall pruning should generally be avoided, because new growth can often be too tender to withstand the cold and windy weather of the impending winter. Two exceptions to this general rule are: 1) long wispy branches on ornamental shrubs can be pruned to prevent them from breaking under the stress of a wet snowfall, and 2) damaged or broken limbs of ornamental or productive trees can be pruned in order to create a “clean cut” that will heal faster, and to prevent further damage that would be caused if the branch were left to fall from the tree during the next storm.
For most home gardeners, several pruning tools may be required.
Pruning shears are the basic pruning tool that virtually every gardener should have. We prefer bypass shears, whose blades pass each other, like scissors, when pruning. The other type of pruning shears is known as the anvil type, where one blade performs the cutting action by passing through the plant material and contacting a flat wide blade, known as the anvil. This cutting action is similar to a knife on a cutting board. Anvil pruning shears crush portions of the tissue on both sides of the cut, so that the pruned tree or shrub is somewhat slower to heal and may be more susceptible to scaring and disease.
Pruning shears are used for small limb or branch removal on ornamental shrubs, flowers, and tomato plants.
Lopping shears are big pruning shears that are used for larger branches that can’t easily be pruned with pruning shears. Depending on one’s strength and the quality of your pruning shears, you’ll generally want lopping shears for limbs or branches over a half inch in diameter. Like pruning shears, we prefer bypass lopping shears vs. the anvil design.
A pole pruner is a rope activated lopping shear on a long or telescoping pole. Most pole pruners are bypass lopping shears that are capable of cutting branches up to one or one and a half inches in diameter. Pole pruners can handle branches within 10 to 12 feet from the ground.
Saws are absolutely required for some major tree pruning. Depending on your strength, the density of the wood, and the design of your lopping shears, a saw will usually be required for limbs over one and a half inches in diameter. You can use a folding pruning saw, a bow saw, or a chain saw… all depending on how many limbs need to be pruned and how big they are. Most pole pruners include a curved saw that can be very effective in trimming tree branches that are too large for the shear.
Hedge trimmers are very useful if you have more than a couple of evergreen bushes to be maintained. The Mantis Cordless Hedge Trimmer uses double-reciprocating blades for a faster, cleaner cut, and the Swivel-Click handle swivels 180 for easy, comfortable horizontal and vertical cuts without changing your position. A professional grade hedge trimmer is a lifetime investment that will yield high quality results in significantly less time.
Rose bushes should be pruned in the spring, as soon as new growth appears. Cut off any dead wood, as well as any unwanted branches, just above a live bud. Long spindly branches can be pruned in the fall to prevent any damage from wet snow, which may break the branches.
Fruit trees should be pruned in the spring to remove vertical sucker shoots and any overlapping branches. A good rule of thumb is that you should be able to pass a basketball throughout all or most of the branches of a standard apple tree. Pear trees perform better when most of the fruit-bearing branches are more horizontal than vertical.
Woody ornamentals should be pruned in the spring to maintain a pleasing shape. Be careful not to overprune hydrangeas that bloom on one-year old growth. Flower heads can be removed in the fall; but, all other pruning should be done in the spring.
Evergreens and shrubs should be pruned only in the spring; the objective is to maintain a good shape and the right size for your landscape. Evergreens and shrubs are most easily pruned with electric or gas hedge trimmers, but hand shears can be used if you only need to maintain one or two small shrubs.
Certain herbs, like basil, will produce more abundantly if they’re carefully pruned during the growing season to encourage thicker, shorter branches. We also recommend pruning most of the flower heads from basil during the late summer to increase the herb’s yield. Of course, you may choose to allow some of the flower heads to remain both to attract beneficial insects and to produce seed that you can usually harvest for next year’s crop.
Many flowers benefit from careful pruning, or flower harvesting, during the growing season. One of our favorite zinnias, Cut and Come Again’, sold by Burpee and other seed companies, will produce more abundantly if the early flowers are cut for bouquets and arrangements.