There’s something about this time of the year that makes people eager to start pruning. With fall garden cleanup in full swing, maybe it’s all the raking and mulching that has people going bananas. But before you start hacking at your trees and bushes, take a tip from a seasoned gardening expert.
“The rules of fall pruning are simple: Prune nothing in the fall! That’s nada! Bupkiss! Zilch! Zero!” pleads emphatic gardening expert Mike McGrath, author of Mike McGrath’s Book of Compost and radio host of the radio show You Bet Your Garden. That goes for shrubs and plants as well as trees, McGrath insists. “Hang little signs on your roses that say, ‘Leave me alone until midwinter; or even better, spring,'” he says. “There are no exceptions! Do not prune anything now. Got it?”
Do you feel like you just got scolded by a third-grade teacher? Let it serve as a reminder that fall is not the right time to trim trees and shrubs, even though the fallen leaves have exposed all their imperfections. That’s right, put your pruning shears back in the shed for at least a month or so. Here are some pruning basics, to be used when it’s a safer time to trim back trees and shrubs:
- Why Fall Is the Worst Time for Pruning
- Never Prune When It’s Wet
- Know How to Hack
- Know What to Hack
- Keep Tools Clean
- Pruning for Form — The Tale of 2 Dogwoods
- How to Prune Kousa Dogwood Trees
- Five Common Pruning Mistakes, and How to Fix Them
- “Shape Up” Your Garden
Why Fall Is the Worst Time for Pruning
“As I try to stress every year at this time, pruning them now stimulates new growth just when the plants are trying to go dormant, and this severely weakens the plants,” says McGrath. “Plus, if you prune on a warm day, sap rises up into the plant. Then, it drops below freezing that night, and boom — not a pretty sight.”
Instead, prune in the dead of winter or in early spring, he suggests. That’s if you can’t stop yourself. “Spring bloomers can get a haircut right after they finish flowering. But get over this pruning obsession — few plants other than fruit trees actually require it, and most gardeners do too much, not too little,” McGrath contends.
Still, proper pruning of overgrown flowering shrubs or fruit trees near your house will help the plants produce more flowers and fruit, which can also benefit wildlife. Doing it wisely can also help trees and shrubs give diseases and pests the cold shoulder. Just remember … don’t do it in the fall!
Waiting until winter means that most woody plants are dormant, and because leaves have already fallen, it makes it easier for you to see what you’re doing. For early spring bloomers (like lilacs and spireas) that only need light pruning, prune them just after they finish blooming. For very overgrown deciduous shrubs, winter pruning is probably best.
Never Prune When It’s Wet
As a general rule of thumb, don’t prune when it’s damp outside. “Absolutely, do not prune if it’s wet out, it spreads a lot of diseases,” explains horticulturist April Johnson, landscape coordinator at the Rodale Institute. Damp weather encourages the growth of microbes that will make the most of the damage your pruning does. “Wait until the sun’s out for a little while; it dries out and kills mold and bacteria,” she says.
Know How to Hack
Pruning can allow more sunlight and air to filter through the trees and shrubs, which can help keep them healthy. When it’s time to prune, focus first on removing dead or dying branches. If you see a sickly branch, cut between the diseased spot and the body of the plant. Johnson also recommends pruning when branches rub or cross each other (cut the smaller branch off), or if a branch is growing vertically. You can also take off really low branches that could interfere with foot traffic or lawnmowers.
Cut the branch as close to the source as you can. “I prefer to prune back to the main stem,” says Johnson. “If you leave a stub sticking out, it’s an area for bacteria and insects to harbor.” And make sure you cut at the same angle as the branch collar — the furrow of bark where branch and trunk meet. If you’ve done it right, a circle of healthy callus will eventually swell around the spot.
Know What to Hack
There is a long list of trees and shrubs that you can prune from winter until the sap starts flowing again in spring. Some of them include: glossy abelia, beauty berries, hydrangeas, Bradford and Callery pears, crabapples, poplar, spruce, junipers, sumacs, cherries, and plums. However, because some trees can ooze sap when pruned in the winter, you’re better off waiting until the summer to prune maples, birches, dogwoods, walnuts, and elm trees.
Keep Tools Clean
No matter what type of pruning tools you decide to use, make sure you keep them clean. If you’ve cut out diseased branches, make sure you clean the tools thoroughly before moving on to another tree, to avoid spreading disease. Johnson says you can disinfect the tools by using just a teaspoon or two of bleach in warm water. Hot, soapy water also kills most germs. Remember to dry tools well after washing, too.
And if you can’t trim from the ground using pole pruners, or if there’s any pruning to be done near power lines, make sure you hire a professional instead of climbing high and taking on the dangerous task yourself.
Pruning for Form — The Tale of 2 Dogwoods
I came across an interesting tree pruning situation the other day… Two of the same variety Dogwood trees where one was exhibiting upright growth habit and the other lateral growth habit. This presented an interesting pruning challenge on how these trees should be pruned and a great lesson in pruning for a plant’s “form.”
Same variety of Dogwood tree each with a different growth habit
A customer had salvaged 2 Dogwood trees from demise some years prior and had planted them on their property in the hopes that they would survive. They did but while one pushed for a central leader to bring itself skyward (referred to as an A-Form tree for Apical dominance) the other couldn’t decide which branch was going to lead the way and laid out more horizontally (referred to as a B-Form tree for Broad or open form). What a perfect scenario to document the difference between A-Form and B-Form trees and how each should be pruned!
Let’s look at the A-Form Dogwood tree more closely…
A-Form Dogwood tree exhibiting high apical dominance
The first decision to be made was which branch would be chosen to promote as the central leader. We followed the trunk up from the base and the one we chose was neither the tallest nor largest in diameter but rather the clear extension of the trunk. Then we “headed back” the other branches vying for dominance so as to zap some of their energy and redirect the energy to the chosen leader.
Secondly, we looked for any bad branches that may be dying, broken, rubbing or diseased and removed those. Bad branches need to be removed even if it causes poor visual balance because they can be detrimental to tree health if left unattended.
Then we pruned for lateral growth and started to remove the imbalance of the tree to the far left, a number of branches hanging over the walkway and driveway, co-dominant stems competing for the same space on the trunk or too close to each other, and crossing branches. Our limit of canopy removal for this tree was determined to be 30% and we could have easily exceeded that so as we started to approach the 30% limit we did detail work to balance the tree as much as possible.
A-Form Dogwood tree after pruning. Note: Limit pruning to 30% of canopy
It was helpful for us to pile our debris as we pruned so as to get a visual indication of how much you are removing (bottom right hand corner). We would have liked to continue pruning this tree but reached maximum 1-year pruning so had to stop. This tree will be pruned again next year and most likely the year after as well. Well maintained trees can be pruned as little as once every 3 years and that is the long term goal for this tree to get it on a 3-year pruning cycle with just minimum touch up during the year.
And what about the B-Form Dogwood tree?…
B-Form Dogwood tree exhibiting low apical dominance
The first step was to assess whether or not the tree had the ability to support a main central leader. Dogwood trees typically exhibit a moderate apical dominance but this tree had been so abused prior to our customer rescuing it that to reestablish strong apical dominance would take years of training. The time and expense of doing so coupled with the low aesthetic value while the tree was being retrained was not something our customer wanted to invest in so we chose to treat this Dogwood tree as a B-Form tree.
First up was cutting what appeared to be multiple sprouts but were in reality just lateral branches trying to express central leader tendencies (apical dominance). We used mainly “reduction” cuts taking the vertical branches off at the lateral branches. This was different than what we did with the A-Form tree where we “headed-back” the other branches vying to be the central leader instead of taking them off at a main lateral branch.
After reducing the vertical leaders we then checked for and removed any bad branches that may have been broken, cracked, diseased or rubbing.
Then we went into the lateral branches to bring the tree back into some sort of shape. Branches were removed that hung over the sidewalk or were hanging on the fence. Some of the low hanging branches were “removed” at the trunk to get a more moderate tree-like shape. Competing laterals were reduced and branches that were either growing too close to each other or crossing were also reduced or removed.
B-Form Dogwood tree after pruning
This tree also reached it’s maximum 30% removal before we were ready to stop so we put this tree back on the list to be pruned again next winter. While both trees could still use some pruning they are now healthier having removed bad branching and much better looking.
A final note: Both trees exhibited stressful conditions during their early years. The A-Form Dogwood had pock marks from where a woodpecker had searched for insects under the back layer. As such, we recommended a deep root feeding to get nutrients and biological life down around the root structure as quickly as possible to help the trees be as healthy as they can be. Good nutrition and proper watering will be important for the long term viability of these trees. For additional information on our deep root feeding procedure go to: https://www.earthdanceorganics.com/organic-solution-for-verticillum-wilt/.
And for your information: We used 3 pruning-cut terms in this article: Removal, reduction and heading-back. Removal cuts take the branch off at the trunk or point of origin; Reduction cuts takes the parent branch back to a significant lateral branch; And Heading-back cuts shorten a parent branch in between insignificant lateral branches.
How to Prune Kousa Dogwood Trees
Small White Flowers image by Van Ness from Fotolia.com
Kousa dogwood is a species of flowering tree native to Japan and Korea and is a relation of other Cornus species native to North America. They are prized for their large bracts in spring, decorative red berries in summer and their richly colored fall foliage. They do not require regular pruning, except to remove occasional damaged or dead wood. If they require pruning, it should be conducted immediately following bloom in the late spring or early summer, according to Purdue University. Kousa dogwoods produce their flowers on year-old wood.
Cut out any dead, cracked, abrading or otherwise damaged branches. Place the cut back to a point of healthy wood or back down to the parent branch from which the problem branch originates. Place all cuts on the bias just 1/4 inch above a leaf node or bud or just outside of the slightly swollen branch collar where two branches meet.
Thin the interior of the canopy if needed to increase sunlight penetration and fresh air flow. Prune away branches that grow inward toward the trunk and those that cross or abrade one another. Spread the thinning cuts throughout the canopy evenly to preserve a balanced shape.
Reduce the length of the branches only when needed to improve access around the tree, such as when it overhangs a walkway or is brushing up against another tree canopy or structure. Remove just the branch length necessary and place the cuts 1/4 inch above a leaf node or bud.
From your photograph, it appears that your dogwood is healthy and growing well. As it grows, it will develop its characteristic horizontally-branched, mounded shape. Here are a couple of things to consider.
It is possible that your conditions are not ideal for favourable development of your dogwood. Although it will grow in conditions ranging from sun to shade, it flowers most vigorously in full to partial sun. Assuming it is a Cornus florida, it also prefers an acidic soil: it may be worth having your soil pH tested as this plant is highly sensitive to soil pH. In addition, if your soil is dry, poor or compacted, your dogwood will struggle to thrive. Mulching around the base of your tree is helpful in providing good soil nutrients – making sure that you leave some space between the mulch and the tree trunk.
If you wish to selectively prune some of your lower branches, or any that crowd or cross other branches this should be done in late winter or very early spring before you notice new growth. Dead or diseased branches should also be removed. Topping your flowering dogwood is not recommended for encouraging stronger growth – in fact, it may promote growth that is weaker and it will destroy the shape of your tree.
If you are in a part of British Columbia where winters are very mild, you might wish to consider contacting the British Columbia Master Gardeners Association who could provide advice that is tailored to your location: https://www.mgabc.org/
Five Common Pruning Mistakes, and How to Fix Them
Have you ever pruned so ineptly that your tree or shrub looks like a caricature? Well, don’t despair. Help is at hand for five common pruning disasters.
Photo/Illustration: Danielle SherryYou needn’t weep for this weeping cherry, a victim of Mistake #3. It can be restored to its natural form with a few well-placed cuts.
Photo/Illustration: courtesy of Erik DraperIs this the best way to keep a tree small? Probably not. See Mistake #4 for the solution.
Photo/Illustration: courtesy of Erik DraperSnipping the tips of branches is a bad pruning habit. See Mistake #1 for best practices.
Photo/Illustration: courtesy of Erik DraperPhoto/Illustration: Judy SimonPhoto/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo by Anneli Salo under the Creative Commons ShareAlike 3.0 Unported License. Photo/Illustration: Judy Simon Photo/Illustration: Danielle Sherry Photo/Illustration: courtesy of Erik Draper Have you ever pruned so ineptly that your tree or shrub looks like a caricature? Well, don’t despair. Help is at hand for five common pruning disasters.
Photo/Illustration: Danielle Sherry You needn’t weep for this weeping cherry, a victim of Mistake #3. It can be restored to its natural form with a few well-placed cuts.
Photo/Illustration: courtesy of Erik Draper Is this the best way to keep a tree small? Probably not. See Mistake #4 for the solution.
Photo/Illustration: courtesy of Erik Draper Snipping the tips of branches is a bad pruning habit. See Mistake #1 for best practices.
Photo/Illustration: courtesy of Erik Draper Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo/Illustration: Judy Simon Photo by Anneli Salo under the Creative Commons ShareAlike 3.0 Unported License. Photo/Illustration: Judy Simon Photo/Illustration: Danielle Sherry Photo/Illustration: courtesy of Erik Draper
There is nothing less noticeable than an excellent pruning job. But on the flip side, there is nothing more noticeable than a poorly pruned plant. Pruning is a science and an art. The science involves recognizing plant flaws and skillfully
eliminating or minimizing these defects. The artistic end involves removing these bad parts or pieces with a disguised grace so that the plant appears unmarred and untouched. As gardeners, though, we sometimes forget about one of these aspects when pruning, and that’s when we make mistakes.
| A brief glossary of pruning terms
Have you ever tried to read a book on pruning and felt like it was written in a foreign language? Don’t worry-you’re not alone. Here are some common terms to demystified:
APICAL BUD The bud that produces new growth, typically located at the tip of a branch; also known as the dominant or terminal bud
AUXIN A growth hormone found in apical buds that promotes cell division (new growth) and inhibits any lower buds from growing
LATENT BUD Any bud-typically below the apical bud-that remains dormant or underdeveloped for a long time but may eventually grow
LATERAL BRANCH Any branch or minor stem that grows off the leader
LEADER The main or dominant stem of a plant
MAIN SIDE BRANCH A large lateral branch that is usually only slightly smaller in diameter than the leader
Everyone can relate to that feeling of panic after making a cut and realizing that you’ve just ruined the shape of your shrub. Or perhaps you’ve ignored a plant’s obvious structural problem because you were afraid or unsure of what pruning action to take. Improper pruning can lead not only to ugly plants but also to liability in the landscape. There is some recourse, thankfully, for these errors in pruning judgment.
Here’s are links to the five pruning mistakes I see most often and advice on how to fix them to save your plants and your sanity.
Pruning mistake #1
You keep snipping the tips of your plants to keep them in check.
Pruning mistake #2
Your conifers are out of control in summer, so you cut back the longest branches.
Pruning mistake #3
You shear your weeping cherry tree so that it looks like it has a Beatle haircut.
Pruning mistake #4
The tree in the front yard is too tall, so you chop off the top to make it stop growing up.
Pruning mistake #5
You decide not to prune.
This article, by Erik Draper, was originally published in the January/February 2011 issue of Fine Gardening (#137) under the title “Oh no! Now what?”.
Illustrations: Judy Simon
Photos courtesy of Erik Draper, except where noted
Pruning mistake #1
You keep snipping the tips
of your plants to keep them
|Prevent rampant regrowth and the oversnipped look by making a few large cuts, leaving just the most vigorous branch of the cluster.|
Why it’s bad: We sometimes think that too many large cuts will hurt the plant but that smaller cuts won’t harm anything. In reality, snipping the tips of branches (stubbing out) is one of the worst pruning mistakes you can make. Pruning stimulates the plant to grow, so when you snip the tip of one branch, four to six new branches take its place. This abundance of new branches happens because removing the tip of the branch also removes the apical (dominant) bud, which chemically inhibits the buds below from growing. When the profusion of new branches grows, the typical response is, again, to snip off the new branches-and so the vicious cycle of snipping begins.
How to fix it: Making a few large cuts-rather than a gazillion smaller cuts-is the best strategy. But if you are in the middle of a snipping nightmare, you need to allow all the multiple new branches to grow from below the pruning cut. At the end of the growing season (late summer to early fall), select the strongest and most vigorous branch of the bunch, making sure that it is growing in a desirable direction. Remove all the other competing branches back to the trunk, if possible, or back to the main supporting limb. This will ensure that the selected branch will have a dominant bud, preventing the branches below from growing back.
Pruning mistake #2
Your conifers are out of control
in summer, so you cut back
the longest branches.
Why it’s bad: It can be a pain when conifers become too large, grow too fast, or just plain get in the way. The natural reaction is to remove the portion of the limb that is causing the problem and no farther back than absolutely necessary. But this always leaves a branch stub sticking out.
If pruned incorrectly, conifers rarely-if ever-recover. Most of the new growth on a conifer is generally derived from buds formed on the previous season’s growth. The new buds are mainly on the ends of the branches and expand in early spring to form the new growth (also called “candles”). Cutting back into the older wood on the branch, beyond where the new growth buds are located, usually results in a permanent stub, which is also known as an “eye gouger.” It is always brown and always ugly.
How to fix it: If you have a shrub or tree with branch stubs, you need to remove the stubbed-out branch all the way back to the trunk or cut back to the nearest healthy lateral branch. If pruning is done early enough, new buds will develop near the cut for the following season’s growth.
Pruning mistake #3
You shear your weeping cherry
tree so that it looks like it has
a Beatle haircut.
Why it’s bad: Sometimes we see plants as geometric shapes in a landscape but forget that they grow and change. A gardener may like a plant for its color or fragrance but not its natural form. The problem is that, despite diligent pruning, the darn things keep growing into places they shouldn’t. The more you shape the plant, the denser it becomes, and eventually, it starts to die from the inside out.
How to fix it: Complete removal of a plant is better than constantly fighting its natural size or shape. Remember that a plant’s growth habit is genetically predetermined and that pruning will never slow plant growth. For plants that have been subjected to years of repeated shearing and shaping, you need to selectively thin those dense areas overloaded with branches. Remove entire sections of branches back to the trunk, working from underneath and inside the plant. Leave the outfacing (scaffold) branches in place. This allows sunlight to penetrate the plant’s interior, which stimulates latent buds to grow normally rather than in a bunched-up fashion. Continue to thin and remove these dense branch clusters every year, making cuts deeper into the plant. Ideally, you’ll want to achieve a balance between the long scaffold branches and the smaller lateral branches inside.
Restore a weeping cherry to its naturah arcing form by thinning the overloaded areas to let sunlight in. Leave the scaffolding branches in place.
Pruning mistake #4
The tree in the front yard
is too tall, so you chop off
the top to make it stop
Why it’s bad: Although most topping tragedies happen because we want to maintain a plant at a specific height or to keep it from growing too fast, some plants lose their tops (main leader) due to insect damage, disease, or even heavy birds landing on tender new growth and snapping it off-it sounds far-fetched, but I’ve seen it happen. Topping plants or cutting the central leader is fine when you want to make a scrawny shrub broad and full, but it is a nightmare for trees. Removing the tops of the tree causes the tree to create several new leaders to replace the ones lost. These leaders compete with each other and compromise the structural integrity of the tree; trees with one dominant central trunk fare better when faced with wind, snow, or ice storms. Also, remember that a pyramid is the most efficient shape for harvesting sunlight and, therefore, for maintaining plant health.
|How to fix it: With conifers, select the most vigorous lateral branch below the nub of the former leader and simply bend it up. Using masking tape, attach the bent lateral branch to the main stem of the tree. Masking tape is effective because it eventually breaks down, loses its adhesiveness, and drops away without girdling the newly trained leader.||How to fix it: With deciduous trees, select and reestablish one vigorous leader. Keep this adage in mind: “Leaders lead and are the highest up.” Prune out any competing leaders or overly aggressive lower branches so that the remaining branch becomes dominant.|
A double leader is just as bad as no leader
A double leader is just as bad as no leader In the case of tree leaders, two is not better than one. A tree with a double leader is a huge problem because heavy branches develop on the outside of the two main stems. This weighs down the two leaders and strains the spot where they are joined, eventually splitting the tree.
To fix this landscape hazard, select the strongest and straightest of the two leaders. Make a 30- to 45-degree cut on the other leader to remove it. This ensures that moisture, which causes rot, doesn’t remain on the pruning cut.
Pruning mistake #5
You decide not to prune.
The brilliant red stems of Cornus alba fade as they age. Photo by Anneli Salo under the Creative Commons ShareAlike 3.0 Unported License.
Restore the color to your twig dogwoods by pruning out stems that are more than two or three years old.
Why it’s bad: Not pruning is probably the most common pruning mistake among gardeners. Some are fearful to make drastic cuts because they think it will cause more harm than good; others worry that any pruning will leave unsightly holes or set back the growth of a plant. Years later, they can’t understand why their redtwig dogwood (Cornus alba and cvs., USDA Hardiness Zones 2–8) doesn’t have brightly colored stems anymore. Without pruning, the desired coloring will disappear because it is the new growth that has the brightest hues.
How to fix it: One word: Prune. For shrubs with intense bark colors, lneed to remove the older, colorless branches. For shrub dogwoods, these branches will be those that are more than two to three years old. Dogwood stems should be removed as close as possible to the base (crown) of the plant. This removal stimulates the plant to produce new wood in beautiful colors.
Learn more about pruning tools, basic techniques, and pruning specific trees and shrubs, including roses. See Pruning Tips and Techniques for links to dozens of articles and videos from Fine Gardening‘s experts.
“Shape Up” Your Garden
Trees add immense value to the landscape, both aesthetically and economically. Properly pruning young trees improves their health, vigor, and structural strength. A well-maintained tree is less prone to pest and storm problems and lives longer. And of course, structural pruning improves the visual appearance of a tree for years to come. Here are the steps to follow if you are looking to “shape up” the trees in your garden.
After planting, pruning should be limited to broken or damaged limbs for the first year. During the first growing season, newly transplanted trees need as many leaves as possible to produce energy for root growth and establishment. Take advantage of this time to study the tree’s form and identify potential weaknesses, such as crossing branches or narrow branch angles.
Selecting Main Branches
Structural pruning may begin in the second growing season. The goal is to establish a series of strong branches that are evenly spaced along and around the trunk. Typically, the main branches or scaffold branches are spaced in a spiral pattern up the trunk. On large shade trees like oaks and maples, these branches may be spaced 18 to 24 inches apart. On small ornamental trees such as Empress of China® Dogwood, scaffold branches may be closer together – about 8 to 12 inches apart. These branches provide the main framework of the tree. It can take several years of selective pruning to establish a series of scaffold branches.
Making the Cut
Determining which branches to keep and which to remove may seem challenging. Start by removing branches with weak angles of attachment to the trunk. Narrow branch angles are more likely to split during storms. Remove branches with V-shaped angles or those less than 45 degrees. Strong branches have a wider angle of attachment – between 45 and 90 degrees. These make the best scaffold branches. Other branches to remove include those growing at odd angles across or through the tree, and rubbing or crossing branches.
It is important to note tree branches do not move up vertically from the ground as the tree grows. They generally stay the same distance from the ground, with new growth adding additional branches higher in the canopy. Consider the branch position and try to picture the tree’s appearance as the scaffold branches grow in diameter. Walk around the tree and step back, comparing both the vertical and radial position of each potential scaffold branch before making a selection.
Raising the Canopy
Gardeners often choose to limb up lower branches to raise the height of the canopy. Approach this process slowly to maintain protection of the trunk during the first several winters. Many young trees have thin bark that is susceptible to sunburn and winter injury. Therefore, it is important to maintain some lower branches to provide shade to the trunk. As the tree matures, these limbs can gradually be removed until the canopy is at the desired height.
Structural pruning is a gradual process and will take a series of cuts over a few years to complete. When working, step back each time you remove a few branches and walk around to determine if any more cuts are required. At each pruning, no more than one-fourth of the tree canopy should be removed. As the tree takes shape, you will be rewarded for your patience.