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In its fourth winter, this tree has four well-developed leaders (see "Open-center training,"page 4).

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BasicprinciplesWhy train fruit trees?

Training develops a strong treestructure that can support heavy cropswithout breakage.Training helps to bring a young treeinto production at an early age.

Why prune fruitand nut trees?

Pruning reduces overall tree size.Pruning makes trees easier to sprayand harvest.Pruning young trees can improvestructural strength and inducebranching.Pruning mature trees can increase theirproduction and improve the fruitquality.Pruning reduces the need to prop upthe fruit-laden branches.

Don't use wounddressings!

They're not necessary - there's noclear evidence that they reduce wood rotsassociated with pruning wounds. Treesprotect themselves from wood-rottingfungi by producing a chemical barriernear a properly made pruning wound.

Robert L. Stebbins, Extension horticulturespecialist, tree fruit and nut crops, OregonState University.

6OREGON STATE UNIVERSITY EXTENSION SERVICE

Figure 2.In a poorly pruned tree, upperlimbs shade out lower limbs, and a densethicket of "suckers" appears in the top. Cutthe drooping terminal portion to a moreupright branch. Remove some of the"suckers," cutting close to the limb; thin outside shoots on others so that they'll bend overwith the weight of the fruit.

Figure 1 . When you prune, don't leave astuband don't make a wound larger thannecessary, which happens with a "flush cut."Cut lust outside the tapering portion of thebranch, where it's inserted in a larger branchor the trunk.

Figure 3.On this well-pruned branch,thin out more shoots toward the end(those colored red).

Figure 4. Thiheight, cut whccolored red).

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Prune so that you don't leave a stub(figure 1), but also so that you don'tmake a wound larger than necessary, asoccurs with a "flush cut." Cut justoutside the tapering portion of the branchwhere it's inserted into a larger branch orthe trunk.

Early tree training helps you avoidlarge pruning wounds low in the tree,which might become infected.

General rules for trainingStart following a training system atplanting time.Remove unwanted shoots in summerwhen they're small.Train more by limb positioning thanby pruning.

Follow the training program consis-tently, as frequently as necessary, sothat you complete training properly assoon as possible.

General rules for pruningPrune all fruit and nut trees at plantingtime to balance the tops with the rootsYou'll need much less pruning atplanting if you plan to irrigate theyoung tree frequently during itsestablishment.Prune young trees very lightly.Prune mature trees more heavily,especially if they've shown littlegrowth.

Prune the top portion of the treemore heavily than the lower portion(figure 2).Prune when all danger from fall orearly winter freeze has passed, butbefore full bloom in spring. Sweetcherry trees may be pruned in Augustwhen there's less danger of bacterialinfection.Thin out more shoots toward the endof a well-pruned branch in a maturetree. This will increase fruit size andquality on the remaining shoots (figure3).To reduce the height of an excessivelytall tree, cut whole limbs out of thetop, making cuts flush with the bark ofa lower limb. Stubs left in the top of atree won't heal (figure 4).

Limb bending

Bending nearly vertical limbs to anaspect 45 to 60° from vertical usuallystimulates fruit production earlier in thelife of the tree. The thicker and moreupright a limb is, the more benefit it willreceive from bending. Early productionstimulated by bending helps to keep atree small and manageable.

Open-center training (figure 5). Totrain trees to an open center, choose threeor four shoots to form main scaffoldbranches the first winter. Remove othershoots that might form competing limbs.Head them, removing a fourth to a thirdof their length, if they're long andunbranched.

When you remove large limbs, first cutpart way on the underside. Don't leavestubs.To keep a tree small, prune moderatelyevery year and don't apply fertilizer,manure, or compost. (This doesn'tapply to "dwarf" trees.)

Central-leader training (figure 6). Ifa nursery tree has few or no branches atplanting, head it at 24 to 30 inches aboveground. To train trees to a central leader,choose a vigorous shoot high on the treeafter planting.

During spring or early summer,remove other shoots near it that, becauseof their upright aspect and vigor, will

A

compete with the lead shoot (figure 7).Head this shoot by a third each dormantseason, and tie down or removecompeting shoots.

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I,,Figure 5.To train trees to on open center, you'll need fourseasons (red indicates removed or headed shoots):

A The first winter, choose three or four shoots to form mainscaffold branches; remove or severely head all others. Scaffoldbranches should be at least 8 inches apart on the trunk for astrong tree structure.

B The second winter, choose one or two more.C By the third winter, scaffold selection should be complete.D The fourth winter shows a good open center. Four main

scaffold limbs evenly distributed around the trunk are enough;a fifth limb crowds.

Figure 6. To train trees to a central leader, you'll need four seasons(red indicates removed or headed shoots):

A The first winter after planting, choose a vigorous shoot high on thetree. Cut off the top in to stimulate branching if it's 2 feet long orlonger. Head all other vigorous shoots more severely.

B, C, and D. Repeat the process the following three seasons so that noside branches become vigorous enough to compete with the centralleader.

Figure 7. The highest portion of ascaffold limb is called the "leader." Thin itto an upright side shoot. Head that shoot

all upright shoots that mighte. To avoid overgrowth in the tree)eat this process annually.

Before After

Sprearequiredthe folio'branchescompete

Dwarf apple varieties that have wide-angled limbs naturally (such as Liberty,shown in figure 6) don't require heading orspreading if they're supported. Delicious,Newton, and other varieties with narrowcrotches or upright limbsor bothdo re-quire spreading. The central leaders of non-supported trees need annual heading todevelop short, stout limbs.

Figure 8.While the tree is young, spread branches that make very narrow angles with themain trunk. If such limbs are allowed to grow to a productive age, they usually break out,often splitting the entire tree.

Figure 9.Thinning out (left) and heading back or "stubbing" (right).

Thinning out and heading back(figure 9). Thinning-out pruning resultsin long, flexible limbs that bend downwhen loaded with fruit. Heading back or"stubbing" causes limbs to branch andstiffen. Light heading stimulatesbranches when you train young trees.

Fruiting habits

Figure 10 shows the difference infruiting habit between peach and apple.Peaches bloom only on 1-year-old wood;apples usually bloom on spurs orshoots from 2-year-old wood.

Figure 11 shows a mature apple tree'sfruit spurs, which will bear the fruitcrop. Because peach and apricot treesbear only on 1-year-old wood, theyrequire more annual pruning to renewfruiting wood than apple and pear treesdo. Cherries and prunes require relativelylittle pruning.

Figure 10.One-year-old wood is wood thatgrew during the previous summer: peach(left), apple (right).

Figure 11 . The fruit spurs on a mature appletree bear the fruit crop.

Figure 12.Espalier training.

Figure 13.Palmette training.

Espalier andpalmette training

Espalier and palmette trainingdevelops trees in two dimensions only.In a home garden, you might use it tosave space and to enhance the estheticappeal of fruit trees. You can do it mostsuccessfully with dwarf apple and peartrees. Select buds to form the branches atthe proper height and cut off the tree justabove them.

As these buds grow - and beforethey've produced enough wood tobecome stifffasten the shoots that growfrom them to training wires or sticks withmasking tape or other suitable material.

Develop the lowest branches first,angling them at about 30° at the start.Widen this to 45..5Ø0 when they're as longas you want them (figures 12 and 13).

By heading the central leader justabove where you want branches, developone or two higher pairs of branches,keeping them shorter and slightly morespreading than the lower pair. It's best tohave at least 18 inches vertically betweenbranches.

Balance the growth of limbs bybending strong limbs down more or weaklimbs up more. Withhold or applyfertilizer to keep growth within desiredbounds.

ToolsLong-handled pruning shears (figure

14, center) are the most useful tool foralmost all pruning jobs.

Hand shears (figure 14, bottom) areuseful for training young trees.

If you need to make large cuts, use apruning saw (figure 14, upper left).

Use only a sturdy stepladder. Set itfirmly on the ground to preventaccidents.

Applyingthe basicsApple trees

Fully dwarf trees. You must supportthese trees in some way, or they'll bendto the ground under the weight of theirfruit. You could support the central trunkagainst the side of your house or a fencewith adjustable eye-bolts or tumbucklesand wires.

If you use individual posts, make surethey extend at least 6 feet above theground, and drive or sink them at least 2feet into the ground. Wooden tree stakesshould be 2 inches or more in diameter.

You can grow dwarf apple trees on apost-and-wire trellis in a hedgerow. Postsmay extend from 6 to 10 feet above theground. Treated posts are best, butsound, untreated 4 x 4 cedar posts maybe satisfactory. Use galvanized wire, 12gauge or heavier. The lowest wire shouldbe about 4 feet above the ground, withhigher wires at 2-foot intervals.

Anchor the end posts against anotherpost driven several feet into undisturbedsoil at an opposing angle. Tie the maintrunk to these wires, using a loop bigenough to allow the trunk to grow

Figure 14. Pruning saw (upper left), long-handled pruning shears (center), hand shears(bottom).

without being girdled. If you attach thetrunk to the trellis wire with 5/8-inch boxstaples, it will graft to the wire and notgirdle.

Train fully-dwarf apple trees to acentral leader (figure 6). If you trainthem to a central leader, and supportthem from a post or trellis, they'll makehighly productive 6-, 8-, or 10-foot trees.

If you don't train them in this manner,the weight of the fruit will bend themdown so that they make bushlike treesonly 4 or 5 feet tall.

In the spring following planting, whenshoots are 3 to 4 inches long, select theuppermost vigorous shoot and removeother shoots near it. Return several timesin summer and remove any shoots that,because of their upright aspect and vigor,will compete with the lead shoot.

Head this shoot by a third in thedormant season, and tie down or removecompeting shoots. Repeat the process inthe following two seasons so that no sidebranches become vigorous enough tocompete with the central leader.

Keep three to five branches 18 to 30inches above ground to form a basic setof permanent branches. If they'reupright, tie or weight them down to anearly horizontal aspect. Try fillingsandwich bags with soil, sand, or graveland draping them over limbs as weights;use staples to keep them in place duringhigh winds. Position higher limbs tobelow horizontal to reduce their vigorrelative to the permanent basic set.

Semidwarf trees. You can train thesetrees to a central leader or develop themwith three or four lead branches. Centralleader is best for weak-growing varietieson poor soil. Train vigorous varieties

with multiple leaders (when trained tocentral leaders, they may become tootall). In a windy site, use a sturdy stakefor support in the first 10 years.

Head nursery trees the same as forcentral leaders, but develop three or fourshoots instead of one. When they're 4 to6 inches long, spread these shoots usingcocktail-style toothpicks or spring-typeclothes pins.

In the following years, spread or tieout the lead limbs to an overall aspectabout 30° from vertical. You couldweight the side limbs that arise fromthese or spread them to horizontal tostimulate early production. As the treebegins to bear fruit, limbs may requirepropping or tying to prevent breakage.

"Spur-type" trees (figure 15) formmany small spurs on young growth ratherthan the usual long shoots and leafbuds this is how they got their name.

Each spur bears a flower cluster. Theleaves are close together, the treebranches are less frequent, and the treegrows slowly. Because these trees aresmaller than the standard strains of the

Figure 15.on this central leader of a2-year-old spur-type Delicious apple strain,notice the numerous short spurs with blossomclusters. Extensive fruit thinning would berequired to allow this tree to grow and ripenthe remaining fruit.

same variety, and fruit at a young age,they make ideal home-orchard trees.

If you grow them on vigorousrootstocks, spur-type trees may notrequire artificial support until they are inproduction.

Spur-type trees are available on bothvigorous and dwarfing rootstocks.Because they branch sparsely, leave morebranches in a spur-type than in a tree ofstandard growth habit. To train them to acentral leader, space the lower set oflimbs several inches apart vertically onthe leader, and reduce their number tofour or five (figure 6).

Standard trees (full size on seedlingroots). Cut back trees at 24 to 30 inchesfrom the ground at planting time. Trainthem on nondwarfing roots to themodified central leader system: Leave thecentral leader in place until fruitingbegins, then gradually remove it.

It's desirable to have only four mainscaffold limbs, equally spaced around thetrunk and vertically spaced several inchesapart. Develop the main scaffold limbs toan overall aspect just a few degrees abovehorizontal. Make sure that all secondarybranches also have a gradual upwardaspect (figure 5).

The branches of a mature nondwarfapple tree may spread over an area 40feet in diameter and reach a height of 30or 40 feet. Regular pruning, and tyingdown of upright limbs in the top, isrequired to maintain a height of 12 to 15feet. Prune to make the lowest limbs themost vigorous and productive in the tree(figure 16).

Shorten, thin out, and bend down theupper limbs to accomplish this. Byremoving risers that go straight up andhangers that grow straight down from thepermanent limbs, open a vertical spaceof about 3 feet between the lowest limbsand those above, so that light canpenetrate.

If a tree hasn't been pruned for severalyears, it will have a dense thicket ofupright shoots in the top and many weak,pendulant spur systems further down.Prune it back into shape gradually overseveral years, rather than trying to do thewhole job in 1 year (figure 2).

After you identify the main scaffoldbranches, saw out any excess largebranches. Cut ladder bays so that you canplace your ladder in the tree's center.Climb as high on your ladder in the tree'scenter as you intend to pick. and cut themain scaffold limbs down to a height thatyou can reach.

Figure 16. (Above) This old seedling-rooted apple tree is maintained at a height of about 12feet by extending the branches horizontally, rather than vertically. (Below) This enlarged viewshows how the slightly upward aspect of the entire main limb and the terminal part of the sidelimbs maintain a good balance between shoot growth and fruiting. Pruning consists of manysmall thinning cuts.

Remove limbs that lap over or hangdown into other limbs. Thin out theupright shoots, leaving some of thesmaller ones. Cut back weak pendulantlimbs. Gradually invigorate the spursystems by cutting back sonic andremoving others. For better sunlightdistribution, the center of the tree shouldbe fairly free of limbs.

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Don't head shootsremove thementirely or let them bear fruit and rely onthe weight of the fruit to bring themdown. Thin off shoots on the inside ofupright branches so that the fruit willpull them to the outside.

Pear treesHead trees at about 24 inches at

planting. If the top is branched, retainsome branches as leaders. Train peartrees to three or four leaders. Select theseleaders early in the first summer andspread them. Do little or no pruningexcept to head and spread the leadersannually until the tree starts to bear.

Don't head side branchesheadingwould maintain their upright position.Spread or weight all vigorous shootsexcept the lead shoots.

Open ladder bays between scaffoldlimbs, and regularly reduce tree height toone you can reach from your ladder.Shorten or remove upper limbs so theydon't shade the lower limbs. Thin out thebranches of the mature trees and do theheaviest pruning in the tops.

Remove the long shoots in the centerand top, but leave some short shoots andmost spurs. Remove horizontal branchesin the tree top so that they won't producesuckers.

Cut back the slow-growing spursystems to about half their length toinvigorate them, or remove them andreplace with new shoots. On Anjou andComice varieties, cut back most of thespur systems and some shoots to increasethe size of the fruit.

Sweet cherry treesAt planting, head nursery trees at a

height desired for scaffold branches.Cutting a foot or two above ground levelwill produce a shorter tree. Train sweetcherry trees to the open-center system(figure 5) with many scaffold branches.The vertical limbs of young sweet cherrytrees often will grow 6 to 8 feet withoutbranching.

If a young tree is growing very rapidly,cut off a foot or more of new growth afterabout 3 feet of growth has been made inthe summer. This will cause branching.You can hasten production by tying downor weighting limbs to horizontal.

To promote branching on trees notpruned in summer, head every shoot toabout 2 feet in length in the winter. After5 to 6 years, stop heading and thin outcrowded branches.

Bacterial canker, a common disease ofcherry trees, frequently causes gummingand dead areas or "cankers" onlimbsor the death of the entire tree. Ifa gummy dead area encircles most of alimb, you must cut off the limb.

To avoid bacterial infection, whichmight enter pruning wounds, pruningmay be done in August. You can usuallyavoid death from bacterial canker bybudding or grafting the variety about afoot out on the limbs of a mazzardseedling tree.

Mature trees require little pruningexcept as needed to reduce the treeheight. Birds usually eat the top cherries.If you lower the trees too much, the birdsmay eat the cherries you want. If loss offruit to birds is excessive, you may wantto net the lower limbs.

To make netting easier, remove limbsto create a space of about 3 feet abovethe lowest set of branches. Beforeinstalling netting, tie several nearbylimbs together so that you can protectmore fruit with the same amount ofnetting. Remember to untie them later!

Sour cherry treesSince sour cherry wood is quite brittle,

give special attention to developingwide-angled crotches in young trees.Either select wide-angled shoots to formlimbs, or spread the shoots to widen theangles. Three main scaffold limbs isenough for a sour cherry tree.

In the first and second summers,remove excess shoots so that all the newgrowth takes place on the permanentscaffold limbs. Only occasionalthinning-out is needed in mature trees.

Peach treesCut off peach trees about 12 to 20

inches above the ground level at planting.Train trees to the open-center system(figure 5). Develop no more than three orfour main scaffold limbs. Select thescaffolds that make the widest angles atthe point of attachment with the trunk,and not all from one height. Peach limbswith poor crotches split out morefrequently than limbs of many other fruittrees.

Remove the excess scaffold limbs inthe spring of the second year and againin the third year if necessary. Head thescaffold limbs in the first and seconddormant seasons to cause branching untilthere are 6 to 8 secondary scaffoldbranches and 12 to 16 tertiary branches.

Peach trees bear only on 1-year-oldshoots. Enough pruning is required everyyear to stimulate new shoot growth forthe following year's crop. Peach treesbranch readily and have too many weakshoots unless they're pruned properly.

Thin out the shoots, leaving shoots ofmoderate vigor; remove weak or verystrong shoots entirely.

Prune hardest in the tops and near theends of the major limbs. Cut the toplimbs back to side shoots to stiffen themand reduce tree height. Peach trees cropmore consistently and have larger fruits ifthey're pruned heavily. Commonly, up to50% of all the previous season's growthis removed annually.

Prune and plum treesTrain them to the open-center system

(figure 5), with three or four mainscaffold limbs. Prune very lightly for thefirst 5 years. Head only those limbs thatwill be permanent scaffolds.

Japanese varieties (such as Shiro,Redheart, and Burbank) have many long,thin shoots, so heading is far moreimportant in them than it is in mostEuropean varieties.

Weighting or bending limbs stimulatesearly production. Remove the excessscaffold limbs and do little else.

In the mature trees, thin out the topsevery few years and remove the deadlimbs as they appear. Most plums andprunes have ample bloom every year;therefore, only enough pruning isrequired to control height and spread, tokeep the trees fairly vigorous, and toprevent limb breakage.

Walnut treesCut off a newly planted walnut tree 4

or 5 feet above the ground. Unless youdo this, the tree won't grow much forseveral seasons. The lowest limbs of awalnut tree have a habit of drooping, sothey should originate fairly high on thetrunk.

Select three to five main scaffoldbranches in the first and second growingseasons and remove the excess branchesat that time. After the scaffold brancheshave developed, no further pruning isrequired.

Although pruning doesn't hurt walnuttrees, they're so large that it's difficult toprune the tops where pruning would dothe most good. Pruning will invigoratemost old, weak walnut trees.

Filbert treesIn nature, filberts grow as bushes, but

you can force them to grow in a singletrunk by annually removing the sproutsthat arise at ground level. Train themwith three or four scaffolds, similarly topeaches (page 11).

To be most productive, a filbert treeshould make 6 to 8 inches of newterminal shoot growth, on shoots atshoulder height. every year. Frequentpruning helps to maintain this growth.

Prune filbert trees like peaches, butless severely. Filbert wood is especiallysusceptible to wood-rotting fungi. so it'simportant to make cuts at the branchcollar with limbs or trunk.

Apricot treesApricot trees usually develop numer-

ous branches in the nursery. Some ofthese may be selected for scaffoldbranches at planting time. Cut these

branches back a few inches and removeother branches. Cut back long shoots 1year after planting to induce branching.Train the tree similarly to peaches (page11).

Pruning bearing apricot trees is mostlya process of thinning out the excesswood, and heading to shorten longshoots. After a side shoot has producedfor 3 or 4 years. remove it and let a newshoot grow in its place.

Small fruitsSmall fruits need pruning and

attention, too. One or more of thefollowing publications will have theinstructions you need.

They're available from PublicationsOrders. Agricultural Communications.Oregon State University. Admin.Services Bldg. 422, Corvallis. OR97331-2119. Please add 25 shippingand handling for orders up to $2.50. Fororders between $2.50 and $100. add15% shipping and handling. For ordersof $100 or more, please call (503)737-2513 for a price quote.

Strik. Bernadine C.. Growing Black-berries in Your Home Garden, OregonState University Extension ServiceCircular 1303 (Corvallis, 1989). 75

Strik. Bernadine C.. Growing Blueber-ries in Your Home Garden, OregonState University Extension ServiceCircular 1304 (Corvallis, 1989). 50

Strik. Bernadine C., Growing Grapes inYour Home Garden, Oregon StateUniversity Extension Service Circular1305 (Corvallis, 1989). $1.50

Strik. Bernadine C., Growing Raspber-ries in Your Home Garden, OregonState University Extension ServiceCircular 1306 (Corvallis, 1989). 75

Strik. Bernadine C.. Growing Strawber-ries in Your Home Garden, OregonState University Extension ServiceCircular 1307 (Corvallis, 1989). 75

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