removing a larger branch, follow the three- How to get it done cut process to prevent damage to the bark. If no collar or shoulder is present, prune at Pruning Fruit Trees a mirrored angle to the branch bark ridge. Training By Tom Del Hotal Training branches to grow in specific di- rections is often a viable option to pruning. This can take advantage of growth which n the cultivation of all kinds of fruit trees, one aspect of tree care often overlooked is has already developed instead of pruning pruning. Some folks don’t believe in pruning. Others don’t think about it. Still others off already grown branches and waiting for wonder about it but are afraid to try because they don’t know how to begin the task. So new branches to grow. The use of training let’s say you want to prune. Before beginning, you should consider a systematic approach techniques can avoid the wounds made by that first requires knowing a bit about the basics. pruning and therefore reduce the problems associated with those wounds. Pruning Basics to remove a portion of a branch, stem or Training should be done when branches A pruning cut is a wound that is a possi- trunk. Cuts are made without regard to the are young and flexible enough to bend into ble entry point for decay, diseases or insects. position of the cut or to lateral branch attach- shape without breaking or splitting the Plants “heal” a wound by a process called ment. Heading cuts usually result in excessive branch or trunk. Weights, guy wires, stakes compartmentalization. This process sur- branch development below the cut. These or spreaders can be used to train branches. rounds the wounded area both internally branches are usually poorly attached and If ties are used, the tie material should be at and externally with tissue that has greater frequently break off, damaging the branch or least one inch wide wherever it comes into resistance to decay. The wounded area never trunk to which they were attached. contact with the bark of the tree to prevent grows back together and this wound remains damage to the bark. a weakened area for the life of the plant. Making cuts Cutting a small branch and making When making thinning cuts, remove the Reasons To Prune a small wound is always more desirable branch at the top of the collar or shoulder than cutting a larger branch and making a of the remaining branch. This will trigger a Structural strength larger wound. Larger wounds take longer “wound response” which initiates compart- Pruning for structural strength is espe- to “heal” (or compartmentalize) and have mentalization and callus tissue formation at cially important on fruit trees. Heavy crops greater potential for attack by decay organ- the wound site. of fruit can easily break branches, severely isms, diseases and insects. Never leave stubs. The cut will not com- partmentalize, and decay and disease will Types of cuts enter the wound. Thinning cuts — Cuts made to remove Never make flush cuts. This makes a an entire branch or stem at the point of larger wound which takes longer to com- origin, or to remove a portion of a branch partmentalize and also removes the collar or or stem by cutting back to the crotch of a shoulder which is helpful in triggering the branch which is at least one-third the diam- wound response eter of the branch that is being removed, or Never make ripped or torn cuts. When drop crotching. Drop-crotch pruning is a recommended method for reducing the size of a plant in both height and width. Heading cuts / Topping cuts — Cuts made

Pruning principles. The first cut (A) undercuts the Improper pruning cut. If a heavy limb is not undercut, limb. The second cut (B) removes the limb. The final cut it may “peel” back, tearing bark and vascular tissues of (C) should be just outside the branch collar to remove Watersprouts develop profusely following a heading cut. the parent limb. the resultant stub.

8 may & june 2008 fruit gardener damaging main scaffold limbs or splitting hedges, screens or espaliers. so that the tree keeps a balanced shape. trunks. Basic guidelines for structural prun- Prune to a terminal branch to direct growth ing are as follows: Fruit or flowers in that direction. Train scaffold branches to be spaced along Prune to leave flowering and fruiting As branches bend downward from the the trunk both vertically and radially when wood for specific fruit types (fruiting spurs, weight of fruit, foliage, or wood, they often trees are young. last season’s growth—one year old wood, or need to be pruned back into an upright Prune off branches growing on the bottom current season’s growth). growing position. Use drop-crotching prun- sides of attached branches—unless you in- Thin branches and fruiting wood to ing techniques to a side or top branch to tend for a particular branch to become the allow adequate light penetration and air redirect growth. new terminal end of the branch from which circulation, promoting proper fruit devel- it is growing. opment for each fruit tree type. Managing suckers (root suckers) Increase the crotch angles of branches Most deciduous fruit trees are grafted. All to greater than 30 degrees by spreading Size growth arising below the graft or from the branches apart or by pruning off one of the Fruit trees which are pruned to their root system should be removed to prevent branches. maximum size will produce the greatest the root stock from dominating and dwarf- Remove co-dominant leaders by removing amounts of fruit. These trees are pruned into ing out or killing the desired grafted tree. or reducing one of the branches. Occasion- central leader or modified open vase shapes. ally one of the branches can be redirected To keep fruit trees smaller for ease of picking Managing Water Sprouts into a becoming lateral branch by spreading the fruit, to get more trees into an area or Water sprouts are vigorously growing it. This redirected branch will no longer be because of space limitations, prune to modi- upright shoots arising from above the graft co-dominant. Its crotch angle should be fied central leader or open vase shapes. union on grafted trees. In some cases, wa- spread to 30 degrees or greater. Never top or head branches or trees! The only ter sprouts can be trained to form strong exception to this is when you are pollarding branches and may be beneficial. If water Health a tree. Topping or heading has many harmful sprouts are excessively crowded, have nar- Prune off branches exhibiting one or effects on tree growth and tree health. The re- row crotch angles, are crossing or rubbing, more of the four Ds: dead, damaged, dis- sults include excessive, poorly attached branch or are causing poor branch or tree structure, eased or dysfunctional. growth, disease and decay, and starvation they should be removed. among others and never results in reducing Shape the size of the tree long term! Timing Prune trees to specific shapes for the best Reduce the height or width of a tree or Improper timing can predispose plants fruit production. Use the open vase or modi- the length of a branch with thinning cuts to attack by insects, diseases, or damage fied open vase shape for trees in the genus by the pruning technique known as drop- from sunburn or sunscald. Most pruning Prunus; use central leader or modified central crotching. should be done during the winter months leader for all others. Many fruit trees can also on deciduous fruit trees when the trees are be pruned or shaped for specific functions Direct or redirect growth dormant and when insect populations are in the landscape such as shade or patio trees, Manage the growth in the tree so that suppressed by the winter cold. In some one branch or side of the tree does not cases, lighter summer pruning can be ben- overgrow the other portions of the tree and eficial for keeping trees smaller, however many bark boring insects are promoted by summer pruning. If these insects are com- (turn to page 14)

Codominant stems. The nearly equal diameter the two Included bark can be a problem in light crotches. This stems can make them more prone to failure. weakens branch attachment. Drop crotch pruning cuts a limb back to a major lateral. fruit gardener may & june 2008 9 PRUNING (from page 9) on a yearly basis. Good pruning practices end of each limb. will help to reduce the amount of growth Step 4 — Move to the next scaffold mon in your area, keep summer pruning removed each year so that 20–40 percent branch and repeat the procedure outlined in activities to a minimum. branch removal is common. step 3. Again start at the base of the branch and work outwards to the tip of the scaffold Pruning Styles A systematic method to prune limb. Remember to focus on only the scaf- open vase and modified open vase trees fold limb that you are currently pruning. Open vase and modified open vase Step 1 — Remove all suckers. Step 5 — Continue working your way Open vase and modified open vase prun- Step 2 — Look at the entire tree and around the tree, pruning one scaffold limb ing styles are used to maximize fruit produc- determine which branches need to be at a time. If there is more than one layer of tion and fruit quality for fruit trees in the removed or redirected to open the center branches, as in a tree pruned to a modified genus Prunus (peach, nectarine, plum, apri- “bowl” or vase. Use pruning or training open vase shape, move up to the next layer cot and their interspecific hybrids). techniques to open the center of the tree. and continue the procedure outlined in The open vase style resembles a bowl. Step 3 — After the center has been steps 3 and 4. Scaffold branches and secondary scaffold opened up, ignore the overall tree until the Leave sufficient distance between each branches make up the sides of the bowl. All final steps of the pruning process. layer to allow for adequate light to reach the branches that grow towards the center of Start pruning each scaffold limb one at lower layer. Actual distance between layers is the bowl are removed to allow light and air a time, beginning with the lowest scaffold variable and will depend on location, expo- to reach the interior of the tree. limb first. Start at the tree trunk and work sure, tree age and size, branch density, and Low growing or small branches should your way towards the end of the branch. species. Experience will help in determining be left as long as they do not congest this Prune for health, structural strength, and what sufficient distance between layers is. open interior of the “bowl”. These branches flower and fruit production and to thin out Step 6 — When you have finished prun- assist in increasing branch diameter (cali- crowded branches. If branches are growing ing each scaffold limb, one at a time, stand per) and strength as well as help to protect vertically and are crossing limbs which are back and examine the tree as a whole unit. the bark from sunburn. If these branches growing above them, drop-crotch or re- Look for excessively crowded branches, are fruiting branches, leaving these branches move the limb to prevent overcrowding and crossing branches, or branches growing will help bring fruit lower and therefore crossing branches. towards the center of the vase. Remove or fruit will be easier to harvest. After being properly pruned, the overall redirect these branches if necessary. The modified open vase pruning style dif- appearance of the scaffold branch will of- fers from the open vase style by having more ten be feather-like, with side branches and Peaches and nectarines than one level or layer. Each level or layer is fruiting wood mainly attached to the top These trees produce flowers and fruit made up of a smaller “bowl” above and with- and sides of this branch. Small branches on last year’s growth, 1 year old wood. This in the larger, lower bowl. Sufficient distance and fruiting spurs may be attached to the fruiting wood is replaced each year. An must be maintained between these layers to bottom of the scaffold, provided they are average of 40–60 percent of the branches is allow for good air circulation and good light not too crowded. removed each season. penetration to the lower layer or layers. As the scaffold branch matures, the ends Fruiting wood is easily identified. Branch- Large trees can have up to three layers, of the branch will develop into a shape that es have smooth, shiny, green or green and so that the overall appearance of the tree re- resembles an outstretched arm and hand, brown bark. Branches have well developed sembles candelabra. This results in a larger with the “fingers” of the hand pointing up- buds but no side branches. Branches are fre- tree and greater fruit production than the ward and the “palm” of the hand directed quently pulled downward by the weight of open vase style. towards the center of the tree. Branches the fruit and develop into “hangers,” which Open vase shaped and modified open should be spaced along the scaffold limb, are beneficial to picking the fruit. vase shaped trees will need to have an aver- alternating from side to side. The “fingers” age of 40–60 percent of growth removed and hand should form an open “cup” at the Plums and apricots These trees produce flowers and fruit on fruiting spurs. Fruiting spurs are long lived FRUITING HABITS OF COMMON FRUIT AND NUTS on plums (up to 10 years) but are short t h i s c h a rt s h o w s t h e p o s i t i o n o n t h e branch w h e r e f r u i t w i l l be borne a n d t h e type a n d a g e o f w o o d t h a t bears f r u i t Current Season’s Previous Season’s Previous Season’s Long-lived Spurs lived on apricots (3–5 years). Shoots Shoots Spurs and Shoots Fruiting spurs develop on branches that Fig – second crop Fig – first crop Apple – minor Almond are two years old and older. These older Persimmon Filbert Cherry, sour Apple branches have brown, rough bark and Quince Nectarine Pear – minor Apricot – short-­lived spur Walnut Olive Pomegranate Cherry, sour smaller side branches. The side branches Peach Cherry, sweet may be vegetative, which will produce Pistachio Pear leaves and more branches or they may be Quince Pecan fruiting spurs which will produce flowers Plum, European and fruit. Vegetative branches will produce Plum, Japanese Pomegranate fruiting spurs after they become 2 years old and older.

14 may & june 2008 fruit gardener Fruiting spurs can be identified as The secondary leaders must be spaced branch and repeat the procedure outlined in smaller branches with very short internode along the trunk both radially and vertically step 2. Again start at the base of the branch 1 spacing between the buds (average /4"). to produce a tree with strong branching and work outwards to the tip of the scaffold Vegetative branches are usually larger and structure. Trees should never be topped. limb. Remember to focus on only the scaf- more vigorous, with more distance between Central leader shaped and modified fold limb that you are currently pruning. 1 3 the buds (usually /2– /4" or more). central leader shaped trees will need to have Continue working your way around the tree, As fruiting spurs age and get larger they an average of 20–40 percent of growth pruning one scaffold limb at a time. may resemble “thorns” or become club-like removed on a yearly basis. Good pruning Step 4 — After moving around the tree in appearance. Spurs should be thinned as practices will help to reduce the amount of by working on the lowest scaffold branches, trees age to prevent excessive fruit develop- growth removed each year so that 10–20 continue up to the next higher scaffold ment which results in smaller fruit and may percent branch removal is common. branches and again work your way around cause branches to break. the tree pruning each branch one at a time. Apricot spurs usually die off after 3–5 A systematic method to prune central Step 5 — Repeat steps 2 through 4 until years and need to be replaced. Prune to leader and modified central leader trees you have finally reached the central leader 1 1 remove about /5 to /3 of the older fruiting Step 1 — Remove all suckers. of the tree. Branch height should descend spurs each year after the 4th–6th year. Step 2 — Start pruning each scaffold progressively lower from the central grow- limb one at a time, beginning with the low- ing point, downward as the branches move Central leader and est scaffold limb first. Start at the tree trunk further out from the center. modified central leader and work your way towards the end of the Step 6 — If you a pruning to a modi- Central leader and modified central branch. fied Central leader shape, drop-crotch the leader pruning styles are used to maximize Prune for health, structural strength, and highest, central leader to a lower lateral and fruit production and fruit quality for all flower and fruit production and to thin out round out the overall tree shape by drop- fruit trees except those in the genus Prunus. crowded branches. crotching the taller branches. This style of pruning keeps branches in the If branches are growing vertically and Step 7 — Stand back and examine the center of the tree. are crossing limbs which are growing above entire tree. Look for any crowded or cross- Each scaffold branch and its attached them or are crowding nearby branches, ing branches and drop-crotch, train, or branches and limbs should occupy their drop-crotch, train, or remove the limb to remove these branches. Balance the overall own space in the tree. Branches should not prevent overcrowding and crossing. tree shape by thinning, drop-crotching or cross, touch, rub or be excessively crowded. After being properly pruned, the overall training any scraggly branches. Adequate spacing should be maintained appearance of the scaffold branch will often Fruit trees which are pruned to central between branches to allow sufficient light be feather-like where the branch is horizon- leader or modified central leader shapes and air to penetrate through the tree so that tal, with side branches and fruiting wood may bear fruit on fruiting spurs, as in fruiting wood is produced and so that in- mainly attached to the top and sides of this apples and pears, on last years growth, as sect and disease problems are reduced. branch. Small branches and fruiting spurs in mulberries and some figs, or on current Trees should have sufficient branches may be attached to the bottom of the scaf- season growth, as in figs and pomegranates. remaining after pruning so that the bark of fold, provided they are not too crowded. It is extremely important to know the fruit- the trunk and scaffold branches is protected Where the branches are more vertical, side ing habits of the fruit tree you are pruning from strong, direct sunlight when the tree is branches should be spaced along the branch in order to be able to prune correctly and to full of leaves to prevent damage from sun- in a spiraled arrangement with internode maximize fruit production. burn or sunscald. distance between branches. Adequate thin- A tree pruned into a central leader shape ning of branches should be done to allow for Tom Del Hotal is a certified arborist and has been teaching fruit tree pruning at ______College for more than 10 resembles the shape of a Christmas tree. air circulation and some light penetration. years. Tom is a regular presenter at the annual Festival of Fruit Pruned to this shape, the tree will be the Step 3 — Move to the next scaffold and at chapter meetings. tallest and will produce the greatest amount of fruit. The modified central leader pruning style differs from the central leader by having a more rounded top. The domi- nant leader of the central leader tree is suppressed with drop-crotch pruning or training techniques and secondary leaders are allowed to develop. Each outer leader becomes progressively shorter as they move outward from the center of the tree. These secondary leaders divide the growing energy or dominance between several growing points and the overall effect is a lower grow- ing tree with a more rounded shape. fruit gardener may & june 2008 15