Pruning Your Plants
Intro to Pruning
Proper pruning of your plants will ensure they are healthy and sized correctly for ease of harvest. Pruning also greatly influences fruit production and tree size and vigor. While pruning may be intimidating, it is an important step in the success of your tree, bush, or vine. Without pruning, sunlight will not reach the parts of the tree it needs to, or the tree can quickly grow beyond your control. When in doubt, thin it out! Most people make the mistake of not pruning their tree aggressively enough, rather than over-pruning. Fruit trees are extremely resilient and respond very well to pruning!
Pruning Fruit Trees
Most of the fruit trees that you will be pruning are going to be either pomme fruits (apples, pears, and quince) or stone fruit (peaches, nectarines, cherries, apricots, plums). Depending on your environment, fruit trees can be pruned when dormant either in the summer, or in the winter a month or two before spring. In general it is a bad idea to prune during rainy weather, as this adds to the chances of fungal issues in your tree.
Most of our fruit trees arrive branched, but some are just whips. This is often true with cherries. For branches of most fruit trees to be usable as permanent scaffold branches they must have a wide crotch angle and be two or more feet above the ground.
The first step in pruning is to remove anything that is either dead, damaged, or diseased. Cracked branch? Prune it. Rust or scab? Prune it. You want the tree to focus its energy into branches that are the healthiest and have the best chance of producing fruit. Any branches that are crossing, or heading down, should be removed as well. Also remove any sprouts coming up from the trunk of the tree. When making any cut on the tree, ensure you are cutting at an angle and at the correct location where the branch meets the trunk.
Thinning vs. Heading
In general there are two types of cuts, thinning cuts which removes an entire shoot, or heading cuts which just removes part of a shoot, usually about half its length.
The main goal of thinning is to let light into all areas of the tree to promote fruit growth and ripening. Look at your tree and determine if the branches are going to be competing with each other. If you are letting in enough light, you can get fruit production very low on the tree. You want the general shape to resemble a vase or bowl.
Thinning cuts are what you should use most of the time, as these open up light channels throughout the tree. These lead to an open, vase shaped tree that will produce a lot of fruit.
Heading cuts encourage growth of side branches at the point of the cut on the part of the branch that remains. These are mostly used to establish the short stature of a young fruit tree. These should be done in older wood if possible, to avoid an over-branching scenario. When doing a heading cut, you want to make sure you prune to an outside facing bud. You want the new branches to grow away from the tree trunk, not towards it. Too many heading cuts will lead to a crowded tree with too many shoots that close off light channels and reduce productivity.
You always want to encourage low branching of your fruit tree. 3-4’ off the ground is typical. If your tree does not have any branching and is a whip, you should do a heading cut to encourage low branching.
Some trees that commonly arrive as whips are persimmons, mulberries, walnuts, chestnuts, and cherries. Depending on the tree others may as well.
If trying to prune a weeping variety of tree, you need to stake the tree and allow it to grow up to and harden off at the elevation you want the weeping to happen at. Once the tree reaches this height, prune the tree to encourage this weeping effect.
Unless your tree is a mini-dwarf or other exceptionally small variety you will need to remove what are called temporary branches as the trees matures. Temporary branches are important to the early stages of growth in a tree, but as the tree gets to a mature height they can work against you. Once a tree has reached about 50% of its total mature height any branching 4 feet or lower should be removed. This will improve access to the tree canopy for pruning, as well as removed future disease vectors as branching low to the ground is often damaged by wildlife or becomes weak as it is shaded out by the upper canopy.
Central Leader Pruning
Apples, pears, plums, mulberries and cherry trees are typically pruned to a central leader. Start this pruning by removing limbs with a narrow branch angle because theses usually split from the trunk. Also remove vigorous upright branches that are competing with the leader. Selecting 3 to 5 sturdy branches allows for “scaffold” limbs about 3 feet above the ground. Ensure 2”-6” is kept between each of these branches on the trunk. Space between the layers of scaffold branches allows the light to penetrate and air to move around the fruit which helps it ripen. Prune each of the side branches to about 1’ in length. This seems scary at first, but trust us! Prune the new central leader about 30” above the top usable branch and new branching will begin.
Open Center Pruning
Asian plums, peaches, nectarines, almonds, filberts, paw paws, figs, persimmons, and apricots are typically pruned to an “open center” tree. Select for the healthiest and strongest looking branches with a good crotch angle and at least 6” apart on the trunk, and prune of everything else. Head back these branches to an outside but. The center of the tree will be open allowing light and air to circulate.
Pruning an Overgrown Fruit Tree
If you bought a property that already has fruit trees on it and they have been neglected, fear not. Most people are amazed at how aggressive you can be with pruning and the tree will bounce back. In general, however, if your tree is very overgrown it’s a good idea to take 2-3 years to prune the tree back into shape rather than doing it all in one season. This allows the tree to heal between pruning sessions. As a general rule, no more than 30% of the crown of the tree should be removed at one time.
Pruning Berry Bushes & Shrubs
In general, pruning bushes and shrubs has the same goal as pruning a fruit tree. You want maximum sunlight on all areas of the plant. Use thinning cuts to achieve this. You can shape your bush however you please and can usually keep them at a height that makes harvest east. You should still only be doing these cuts while the tree is dormant, usually Nov-March.
There are several methods of training grapes, but they are all based on establishing a trunk from which new growth is encouraged each year. Prune your new dormant grape plant to two viable buds, from which you will develop the trunk.
Training methods for grapes are based on either cane replacement or spur systems. This is determined by whether a variety produces fruit bearing shoots starting with the first bud, or starting at the 4th-7th bud, of last year’s shoot. Generally, a cane replacement system works with all types of grape, while the spur system does not work with most table grapes.
The vertical curtain method (a cane replacement system) works well for grapes grown in a maritime climate. The fruit is exposed to the sun for maximum sugar and flavor development, and the vines are easily draped with wide bird netting.
The vertical curtain method requires a trellis with wires set at about 3’ and 5’. As the growing season starts, select the most vigorous cane to train up a stake as a trunk, trim out competing side shoots. The first winter head the leader at a bud 2-3” below the bottom wire to encourage branching. Season two select a strong shoot to train along the bottom wire in each direction plus one more to grow up in the center. In the winter keep the two canes on each side of the trunk and prune them to about 15 buds or 2 feet each and tie to the bottom wire. Prune the third upright cane to three buds. In the spring each of the buds will produce new canes, fruiting shoots will be produced from about the fourth bud on of table grapes. As they grow, create a third line of support midway between the bottom and top wire by weaving some twine back and forth between the shoots. Fasten the shoots to the top wire as they get there, and trim at the fifth leaf above the wire (except the three vigorous shoots growing up the center from the three bud spur). The leaves provide the photosynthesis that will ripen the grapes that form at the base of each shoot. Since the vegetation is tied up, it won’t shade the fruit. The following winter and each winter thereafter, prune off the horizontal canes that produced fruiting shoots in summer. Select two replacement shoots that grew from the three bud spur you made last winter. Tie the selected shoots down to the bottom wire (1 in each direction) and prune to 15 buds or about two feet in length. Prune the third upright shoot to three buds. This will produce the replacement canes and spur for the next season and completes the cycle. Winter prune well before new spring growth starts, otherwise cuts bleed profusely. Summer pruned new shoots won’t bleed.
Pruning Kiwi Vines
When you plant your new kiwis, cut dormant vines back to within a foot of the ground. This will encourage the growth of new strong shoots. Choose the strongest and train it up a stake toward the wire or other permanent support. After it is growing well, remove the other shoots. The selected shoot should reach the wire by the end of the first season.
During the winter, head back the shoot just below the wire to stimulate branching. In spring, select and tie in two shoots to train along the wire in opposite directions the next summer. As each female arm grows to 7-10’ along the trellis (males to 5’), head it back and it will form lateral branches that will produce the ‘fruiting arms’. Select side branches every foot or so and cut these back when they reach the outside wire or about two feet in length. After a fruiting arm has borne fruit for two or three years, prune it off just beyond a branch of the current season’s growth, which can grow to be a replacement fruiting arm. This replacement will bear fruit the following season. Repeat this pruning and replacement procedure each year to keep the plant fruitful.