- Create and maintain strong structure.
- Produce a healthy tree with a functional and pleasing form by removing as little live tissue at anyÂ one time.
- To maintain size.
- To improve flowering or fruiting.
- Pruning shears, bypass or anvil. Bypass is best, less damage to tree. Shears prune up to Ã³â€Â branch.
- Pruning loppers. Use for larger branches.
- Pruning saws. Use for larger branches.
- Hedging shears.
Types of Cuts
- Reduction cuts. These are also called heading cuts.
- Removal cuts. These are also called thinning cuts.
Biology of Pruning
- Pruning causes injury and generates a wound response in a plant, but a good pruning cut will allow theÂ plant to heal itself.
- Wound dressings generally only stimulate the economy—use them if they make you feel better.
- Cells at a cut come alive to close the wound. During cold weather these active cells can be injured.
- Think of plants as energy banks, with the energy stored in the branches, stems, trunk and roots.
- Pruning removes energy from the plant.
- Improper pruning can make the energy bank considerably smaller.
- With less energy stored, plant is more susceptible to other problems.
- Keep energy reserves high by removing the minimum amount of live tissue to accomplish your objective.
When to Prune
- Â Donâ€™t prune if you do not know why you are doing it.
- Picking the right tree for the location is the best strategy to minimize pruning.
- One annual pruning of trees in our climate is often adequate.
- More and more research suggests pruning while dormant in spring just before bud swell allows forÂ maximum healing.
- Dead and diseased branches can be removed at any time.
- Summer pruning after leaves harden and are dark green is also OK, but not preferred. This will retardÂ growth.
- Summer removal will slow root growth so do not prune heavily at this time.
- Regular, light pruning (removing < 10%) can be performed on most species at any time. This willÂ promote fastest growth.
- It is better to remove a small amount of live foliage often than a lot all at once.
- For flowering trees/shrubs, remember that when pruning you reduce the number of branch tips, whichÂ reduces the number of flower buds or potential flowers.
- For flowering trees/shrubs, prune after flowering when leaves have hardened and are dark green but beforeÂ new buds set.
- Most fruit trees are best pruned in late dormant season just prior to bud swell.
- Some light pruning in summer is OK for fruit trees.
- Pears and apricots are best pruned in late fall to minimize bacterial infection, especially fireblight.
- Maples and birches prune in winter to minimize bleeding, or sap ooze. Bleeding is not usually harmful.
- DO NOT PRUNE in late summer. This can produce a new flush of growth that is susceptible to frostÂ damage.
- DO NOT PRUNE at transplanting! Removal of branches (unless damaged) reduces root initiation.
- Â Trees with excurrent growth habits generally require little pruning.
- Branches should be no larger than Ã³ the trunk diameter to retain strength. Phased reduction cuts for largeÂ branches.
- If removing a branch, prune on the branch side of the branch bark collar.
- Branch reduction should be taken to another bud or branch. Cut tangential to bud or branch direction.
- Prune while leafless to give you a better view of the structure.
- Pruning increases the chances for surviving a drought by reducing leaves that transpire moisture. Not aÂ good reason to prune.
- Prune for scaffold branches:
- Adequate spacing 8 to 18â€ apart.
- Branches should spiral around trunk.
- Look for good crotch angles and strong unions. Prune out or correct, if possible, poorly angledÂ branches.
- Â Prune out crossing or rubbing branches. Select the best branch to keep, remove the other.
- On excurrent trees prune to single dominant leader.
- Let the pros handle it.
- Shrub pruning much simpler than tree pruning.
- No structural concerns, minimal risk of damage.
- Most shrubs pruned for people reasons, not horticultural reasons.
- The most common reasons to prune shrubs are to thin, and to maintain or reduce size.
- Remove all dead stems.
- Remove 1/3 of the older stems down to 4â€ to 6â€ long.
- Reduce 1/3 of the longer stems down 6â€ to 24â€ inside the canopy.
- Repeat this process each year to maintain a uniform height.
- Allows shrub to maintain original and more natural form without a sheared appearance.
- Cut longer stems deep down into the canopy.
- Leave some foliage intact to form the smaller canopy.
- Consider performing drastic reduction in size over 2 years, doing half the stems one year, the remainderÂ the next year.
- Done on old plants, plants that have lost vigor, or plants that are too large for their site.
- Many shrubs can be cut nearly to the ground in spring to rejuvenate them. Will take a couple years toÂ recover.
- Alternate method is to cut 3 oldest stems to the ground, thin/remove some younger stems. Repeat over 4-5Â years.
Time of Year:Â
- If pruning once/year and flowering is not a concern, do in early spring.
- Many flowering shrubs should be pruned after flowering if you want to have a flower show the next spring.
- It is OK to prune these shrubs anytime if you arenâ€™t worried about the flowers.
- Heavy pruning or size reduction should be done in the early spring.
- Little pruning generally needed on upright conifers due to excurrent structure.
- Leader pruning to a single leader is probably most common, very easy.
- Reduce or remove upright stems or branches to eliminate double leaders or co-dominant stems.
- Removal of lower branches is often done, branches are cut back to main trunk.
- Emerging candles can be pruned to slow growth rate and thicken tree. Do this after candling.
- Most junipers can be pruned anytime. For drastic pruning on branches with no live foliage, prune inÂ spring just before new growth emerges. New growth will generally fill in.
* Information for this handout came from â€˜An Illustrated Guide to Pruningâ€™ by Edward F.Gilman, and â€˜The Pruning Bookâ€™ by Lee Reich.