Fruit Tree Pruning
Published January 27, 2015 By STEVE HOUSER
In general, fruit bearing trees are not all built the same and the type of pruning required depends on the intended outcome and the species of tree. A fruit tree planted in a yard for aesthetic qualities requires a different pruning method as opposed to an orchard grower who wants the maximum amount of fruit production which is simple and easy to pick. Many fruit tree species do not naturally grow in a way that produces a bumper crop. Much of the information on the internet can be conflicting and confusing. Proper pruning helps to produce more fruit that fully matures and has better color as well as taste. Develop a clear objective before you pick up your handsaw and pruners.
Basic Pruning Theory
The tip ends of limbs or terminal bud(s) on any tree will enjoy more rapid growth than the buds growing off the side of the limb before reaching the tip end. The terminal bud (or buds) suppresses the growth of the other lateral buds, which is referred to as apical dominance. The apical dominance is altered when the terminal bud(s) are removed, which allows other lateral buds to become more vigorous and dominant on some species. This forces the tree to produce more fruit on the interior of the tree rather than on the ends of long limbs, which can increase the potential for limb breakage due to excessive end weight. Annual pruning by orchard growers also helps to maintain the size of the tree and encourages sun light and air penetration to the inside of the tree. This helps to reduce the influence of various pathogens plus produces healthier fruit. Even with proper pruning, professional growers must apply various materials during the year to manage problematic insects and bacterial/fungal pathogens that can spoil the fruit. Just because you prune to increase fruit production, does not ensure a glowing and shining harvest moon.
Peach trees are included in the group of fruit trees that require more severe pruning than most.
Basic Pruning Guidelines
A property owner that is primarily interested in the aesthetics of the tree rather than high fruit production will only need to remove dead limbs, provide some branch separation where they rub or cross and minor thinning of foliage and limbs, much the same as pruning a typical shade or ornamental tree. All cuts should be made at the proper angle: http://neilsperry.com/articles/2010/09/29/texas-tree-tips.html and avoid over pruning: http://www.neilsperry.com/articles/2012/07/23/texas-tree-tips.html. As a fruit tree pruned only for aesthetics ages, there is often a need to reduce the weight on the ends of longer limbs because the fruit is produced primarily on the ends, increasing the potential for breakage.
The theory of fruit tree pruning for production does not apply equally to all species. Here is how they are separated:
- Group A includes cherries, jujube, persimmon, pomegranate, and European plums which require the least amount of pruning and do not respond well to topping or heading back lateral limbs. These don`t require much pruning beyond deadwood removal and cuts to encourage a strong structure. These species don`t set strong fruit spurs.
- Group B includes apples and pears which should be kept short in height with tips headed back to lateral limbs to encourage strong fruit spurs.
- Group C includes peaches, Japanese plums, apricots, and nectarines which are pruned back more severely than other fruit trees, but don't develop strong fruit spurs as well as group B.
This peach tree has developed with little or no pruning and will not bear well without help.
For better fruit bearing, the tree has had branch tips removed to create stronger scaffolding.
Only group A is pruned the same as a shade or ornamental tree and these species should never be pruned the same as group B and C.
There are a number of different methods utilized for fruit tree pruning that produce various results. However, they can be confusing to the typical property owner. It is important to first understand the types of cuts that can be made as well as their effect on the tree:
- A topping cut removes a large limb over 2-3 inches in diameter in the outer portions of a tree to just a stump or to a very small lateral limb. Topping removes a large amount of foliage, which is rough on tree health and encourages more leafy growth than fruit. Severe foliage removal should be avoided on all types of trees.
- A heading cut removes the end of a smaller limb under 2-3 inches in diameter to a slightly angled stump or lateral limb of similar size. This cut increases the amount of fruit produced if it is done correctly and forces fruit to grow on lateral stems inside the canopy known as fruit spurs. Cuts are made at a slight angle and preferably, at the juncture of another bud or limb. Fruit spurs have a life expectancy of 1-10 years, depending on the species and heading cuts can encourage a new set of fruit spurs.
Any fruit that forms on these long branch tips would be limited and perhaps cause breakage.
Now headed back, these limbs are ready for improved fruit production on lateral branches.
- A thinning cut removes an entire shoot or stem to the point of its origin. The purpose of the cut is to thin areas of dense foliage or limbs to allow more sunlight and air to reach interior fruit as well as leaves. This cut is used to produce healthy fruit but has less effect on the amount of fruit produced than other types of cuts.
- A drop-crotch cut is typically used on an old tree that is producing little fruit or fruits only on the ends and not inside the canopy. The outer growth of the tree is selectively cut back to a lateral (or side growth) which is at least a third to half the diameter of the parent stem. However, limbs should not be cut back (or drop-crotched) to limbs larger than 3-4 inches. This cut is used to reduce the weight of longer limbs that were not pruned previously or not properly pruned. These cuts on older trees may slow the production of fruit and they can have a negative effect on the health for a few years but they reduce the potential for limb breakage.
- A bench cut is basically cutting back exterior limbs to the exact same point each year. This produces a large amount of sprouts (often called watersprouts or suckers) and increases foliage on the exterior of the tree, which reduces the amount of fruit produced on the inside as well as reducing its quality (looks and taste). Avoid this type of cut and pruning method because it encourages more foliage rather than fruit and increases the potential for sunscald or sun damage due to excessive sunlight on the interior limbs. Too much shade equals no fruit on the inside and too much sun equals sunscald damage to limbs or trunks. If you like a tree that looks like medusa, this is the cut for you!!
Never remove more than 20-30% of the foliage in any given year. It is better to train your tree a little each year rather than try to catch up after missing a few years. Make cuts early and often. Proper pruning for established trees involves removing dead limbs, as well as those that may rub or cross each other, weak branch structures, and thinning areas of dense foliage or limbs, much the same as shade and ornamental trees. This includes trees in groups A, B, and C.
Recently planted trees in group B and C should have heading cuts on the tips to a slight angle rather than flat. By heading back the center, energy is diverted to scaffold or lateral buds which typically grow at a 90 degree angle off the parent stem. The ideal angle for all limbs that branch off a stem or trunk is between 45 and 60 degrees in an upright position but any downward growth can reduce apical dominance and fruit production. Less than 30 degrees or a tight “V” shaped fork will have increased tendency to break under the weight of a heavy fruit crop and requires removing the less dominant stem.
Pears, apples and sometimes apricots will produce a bumper crop but the fruit cannot reach maturity and may not produce next year without thinning the fruit. Fruit thinning is done by hand or a pruning knife and is most effective in the early summer. The amount of fruit to remove varies according to the species of tree, its size, and the amount of crop currently produced.
- The open center method is used on many species and requires removing or cutting back vigorous upright limbs in the center to increase sunlight in this area as well as increased air movement. Species include groups B and C, as well as prunes, and pistachios. Scaffold limbs should be at least several inches apart and separated along the stem rather than congregated close to each other.
- The central leader method leaves one or several dominant or vigorous central leaders with layers of lower limbs that can create a triangle shape. The species includes group B, cherries, and persimmons. The triangle growth form allows filtered sunlight on all sides and through the center. There is also a modified central leader method that begins the same as noted above but as the lateral limbs develop for a few years, a portion of the top is removed to encourage more fruit lower on the tree.
- The bush method is sometimes used for dwarf fruit species and trees in group B and C. Trees are kept small by cutting back all the top growth at least twice a year. As with the bench cut, trees should not be cut back to the same place each year and alter the height of top growth rather than a flat top haircut if you chose this method. Some suggest this method but it is hard on the health of the tree and it has a negative effect on its longevity. Most dwarf species only need thinning or deadwood removal in the dormant season as they age.
- Standard method tree pruning involves the basic care of a tree as previously noted for those primarily interested in the aesthetics of the tree. This method is used for many citrus fruits, figs, jujube, almonds, and pomegranate. As figs mature, cutting back the tips to lateral buds or spurs can encourage better fruit.
During the dormant season after the first year, some of the top is often thinned or removed entirely to allow interior sunlight and air circulation for groups B and C. Dormant season pruning is typically done in January or early February, depending on the weather. Upright and tall vertical limbs are often headed back to strong lateral growth but not removed. Determine which limbs will serve as the primary scaffold limbs in the future. Go easy on pruning in the first few years because it can delay fruit production, especially if the pruning is excessive. Orchard growers often use clothespins, wooden dowels or padded wires between limbs to force the tree to form the best angles of attachment to support the future weight.
This young peach needs to be encouraged with judicious pruning.
Now headed in the right direction, the young peach can grow into a sturdy producer of fruit.
During the second year, limit summer pruning to dead limbs or excessive water sprouts on all three tree groups, typically done in June for many species. Excessive summer pruning before harvest should be avoided as it can delay the maturity of the fruit and reduce the quality of the fruit as well as its size. Limit pruning primarily to the dormant season using thinning and heading cuts (groups B & C) and avoid severe bench cuts. Weak limb structures should be removed anytime as they start to appear as a strong branching habit is an important aspect of proper pruning for all tree species. Sprouts growing from the base of the trunk or roots should be removed as they appear on all trees.
With older fruit trees in groups B and C, the fruit tends to bear more on the exterior of the tree rather than the center as desired for production. Once this occurs, it is difficult to change back to higher fruit production inside the tree and heading as well as drop-crotch cuts are often required. This can invigorate the tree but cause a temporary drop in production. Additionally, reduce or remove vigorous interior sprouts and thin to reduce foliage density, if required.
Heading back larger branches will require a fine-toothed handsaw.
Never prune when a tree is lacking water or during a drought as it can have a negative effect on growth. Also, the newer varieties of dwarf fruit trees should not need pruning other than deadwood removal and encouraging strong structure, as noted previously. Prune no more than you must or it may not produce fruit at all.
Use a bypass hand pruner for smaller cuts under an inch. The term “bypass” refers to the sharp blade passes by the stationary blade and leaves a sharp cut which is cleanly sheared. Cuts over an inch require a fine toothed handsaw to avoid tearing the cut. Avoid the “anvil” style of pruners where the sharp blade is squeezed against a flat anvil as this tends to pinch the wood fibers rather than cleanly cutting them.
Bypass pruners are used here for an all-important heading cut, back to a lateral limb.
There are a considerable number of pathogens that can affect fruit trees and some management can be achieved by proper pruning to offset the problem (scab, cedar apple rust, bacterial cankers, sooty blotch, mildew, fire blight, among many others). Allowing maximum sunlight and air flow to most all of the foliage tends to reduce the spread and effect of these pathogens. Fireblight can cause the loss of apples as well as pears and resistant varieties should be selected. Control involves removing sections of limbs 6-8 inches back from infected areas and sterilizing tools in between each cut. Ten percent bleach with water will work but you must oil your tools afterward or they will rust. 190 proof alcohol will also work, but seem to be a waste of good resources.
If your fruit tree is not producing, it may not be your pruning. Fruit trees often lack a pollinator of the correct species in the vicinity or a lack of bees that assist with pollination. As an example, a Japanese plum will not pollinate a European plum. If you are not sure, check with Texas AgriLife Extension Service or a Texas Master Gardener in your area.
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