Pruning Primer: From Newbie to Ninja
Every gardener has heard that pruning is important. But getting out in the garden and actually doing it is a frightening challenge to many. After all, you’ve worked and waited so long to get those trees and shrubs to grow; now you’re going to lop off some of that hard-earned plant growth?!?
It may seem counterintuitive, but the fact is this:
One of the very best ways to stimulate a plant to grow is to cut it back. Sometimes WAY back.
Pruning controls a plant’s size and shape. It removes dead or diseased branches or limbs. It improves overall structure and health by allowing more light and air into the center of the plant. But, yes, strategically cutting a plant also encourages new growth or flowering. It’s addition by subtraction… and while that may not make much sense from a mathematical perspective, the science behind it will make you a believer once you see the amazing results.
Inside a plant’s terminal buds and growing tips, a hormone called auxin is stored. Auxin’s job is to suppress the growth of other lateral buds below. Think of it as a traffic cop, holding back a line of cars. Only when the traffic cop is gone can those cars that have been waiting on stand-by race onto the freeway.
Remove a plant’s growing tip by pruning and you also remove the auxin. The nearby plant buds are no longer suppressed and will grow rapidly in response to the auxin’s sudden absence. If leaf buds are present on both sides of the branch, you’ll likely get two or more new branches for each one that’s cut.
But make no mistake: pruning isn’t an endeavor to be taken lightly or attempted haphazardly. Once a limb is severed from the plant, there’s no going back. And making that first cut can be intimidating- downright terrifying- even to veteran gardeners. So here are five steps to help you overcome your fear of pruning, taking you from a newbie who’s afraid of the blade to a ninja who wields the steel with utmost precision and skill.
1. Choose your moment wisely.
There’s a time for everything, and some seasons of the year are better for pruning than others. If you’re simply trying to remove dead or diseased branches, go for it whenever the mood strikes. Otherwise, factor in the following considerations.
Anvil style pruners like these cut and crush. They’re best used for clean up of dead limbs and branches.
Late winter/early spring– just prior to new growth starting to develop- is generally the best time to prune. Although pruning does stimulate new growth, this doesn’t apply during dormancy. Most plants and trees utilize stored energy from fall and winter to produce new growth just below the pruning cut when conditions are favorable in spring, once the temperatures and day length signal the appropriate time.
The exception is for trees known for heavy sap flow, like walnut, maple, birch, and chestnut. With these varieties, excessive sap can bleed out of a pruning wound and result in potential stem dieback. Wait to prune these trees in summer, when the leaves will draw sap past the cut, reducing the chances of excess moisture at the wound.
Early/mid-summer– after full leaf expansion- is an acceptable time to prune. Be aware, though, that much of a plant’s stored energy is already gone, used to produce new spring growth. Cut this new growth off now, and it’s wasted. Yes, you will stimulate the plant to put out more new growth, but this extra demand can be stressful to the plant in the summer months, when conditions are likely to be dry and hot and the plant’s reserves are at a premium.
Early/mid-fall is the least favorable time to prune. Pruning now can encourage the plant to produce new growth just as it is sending nutrients and energy into reserves for the cold months to come. Re-routing those reserves can result in new growth that’s weak and more susceptible to damage or death by the colder temperatures. And that creates the perfect access point for over-wintering pests and diseases, especially for evergreens.
2. Know the rule of thumb for your flowering shrubs.
Certain shrubs bloom on new wood, producing flowers on the current season’s growth. Examples include abelia, clethra, and certain hydrangea varieties like Annabelle. These plants should be pruned in late winter; they will produce flowers the same year. For more on this as it pertains to butterflybush, check out my most-read post of all-time.
Other shrubs produce flowers on old growth, wood from the previous year. Azalea, rhododendron, holly, forsythia, and some hydrangea varieties like oakleaf, paniculata, and mophead are all in this category.* Pruning these in late winter would remove all the new flower buds that were formed after last year’s flowering. Shrubs blooming on old wood should be pruned immediately after flowering and before new buds are set.
*Yes, I know that some of you have pruned your mophead/French hydrangeas in spring and still had flowers that summer. It happens; it’s just not the norm.
3. Have the right equipment.
Whether a small handheld tool or long-handled loppers, your pruners will be one of two main cutting styles: bypass or anvil.
Bypass pruners (L) are best for cutting live plant material vs. Anvil style (R) which is best for cutting dead wood
Bypass pruners use a blade that passes by a non-blade part in a cutting action similar to scissors. This type of pruner is best for live plant material when a clean cut is essential and you don’t want to crush the remaining portion of the plant. Personally, I use my trusty Felco #2 bypass pruners (the ones on the left in the above picture) for almost all of my pruning tasks.
Anvil pruners use extra force to squeeze the branch or limb as a blade passes through the plant and stops against the other side of the tool. These are best for cutting dead limbs or when you’re not worried about crushing or damaging the remaining plant material.
4. Pick the place.
As in real estate, it’s all about location, location, location. If you cut too far away from the bud, that new growth you’re hoping for may never be stimulated. Cut too close to dormant leaf buds and they may be damaged to the point that they won’t recover and sprout at all.
To promote new growth, use bypass pruners to make a clean, angled cut about 1/4 to 1/2 inch above an outward facing bud.
For branches with a single bud below your cut point, select a spot on the branch about a quarter- to a half-inch above an outward-facing bud and make the cut at an angle with the high point facing outward.
For stems or branches with buds located in pairs (opposing one another on each side of the branch), make the cut straight across- with no angle- about a half-inch above the bud pair.
5. Know your limits.
How much is too much to prune? That question and a full explanation of your options is easily its own blog post for another day, a good guideline for live plant material is one-third. Measuring from the tip back, take no more than one-third of a total branch or total plant at any one time. True, some plants respond better than others to more severe pruning, your chances of overdoing it are greatly reduced if you stick to this one-third rule.
There is no need to fear pruning. Once you understand that in most cases, pruning is advantageous to the plant, then it’s simply a matter of getting started. The more you do it, the more confidence you’ll have about it. And before you know it, you’ll be pruning like a pro.
Now I’d love to hear from you. Are you a prunaphobic? A wannabe pruning ninja? What’s holding you back from joining the ranks of the fearless black-belt pruner?
About Joe Lamp'l
Joe Lamp'l is the Host and Executive Producer of the award winning PBS television series Growing A Greener World. Off camera, Joe dedicates his time to promoting sustainability through his popular books, blog, podcast series, and nationally syndicated newspaper columns. Follow Joe on Twitter
Great Post. Thanks for sharing this scientific research about diseaes in trees. It was very helpful.
Great Article Joe, Love the show! As a Tree service professional it’s nice to see someone showing the public the things that we do.
Hi. We had some work done in the front yard — taking out the grass and putting in a patio — but we kept two big palms, a queen palm (almost 20 years old) and a king palm (almost 15 years old) . The king palm really got a beating. It’s been almost a year and it’s not doing so well. It’s getting new stalks/palm fronds but they are not opening up. I’ve fertilized it and kind of let it be. We had someone come out and cut back the queen palm and he even said not to do anything with the king palm for now — that was six months ago and there has been no difference. Any ideas? Any good fertilizer you like for palms? Thanks a bunch for all of your great ideas, suggestions and information. I’m going out now to prune some of my smaller plants. Wish me luck.
Joe, I am still afraid of prnuning after gardening for nearly 40 years. I live in WI. Zone 4-5. We still can get frost until May 31. I wait patiently for the hydrangea that have buds formed on old stems. The frost hits them and the buds dry up and fall off. I have no choice but to cut back the hydrangeas back a third of the plant. I have very established plants about 11 years old. This is so frustrating. I do add the proper acid needed for the flowers to turn blue. Sometimes it works. I have made the mistake of cutting back other type of hydrangeas and ruined them . It has been years and the plants have never recovered. I leave the blue hydrangea alone and wait it out. The other varieties like Annabelle I do cut back and they do great. Is there a website telling me which hydrangeas need pruning or not? I look forward to your help.
Hi Robbie. Try this artice, although I’m sure there are other great articles out there to specifically address your questions, I have not looked to see specifically. Here’s one I wrote a while back that does address some of what you want to know: https://www.growingagreenerworld.com/growing-french-hydrangeas-2/
Any tips on pruning an Yoshino Cherry?
I would treat it like any other ornamental tree. The timing suggested in this article (later winter / early spring – before bud break and new growth emerges is what you’re after). Specifically with cherries, you might see a LOT of water sprout branches (small twig-like branching mostly growing up, along the main branches. Cut all of them off right where they emerge from the main branches. While they’re not a major problem, they just crowd the growth and are not aesthetically pleasing to the natural form of this beautiful tree.
Hello! Should roses be pruned or trimmed back before winter arrives in a few weeks? What is the best way to cover them for protection from our rough, cold winters?
Thank you!
Prune roses in winter or early spring before leafing out. Don’t worry about protection. Just add mulch around the base. If the branches die back, new growth should emerge from the base next spring.
Thank you, Joe, for all of the helpful info! My husband (who doesn’t garden at all) and I LOVE your show, and spread the word regularly.
I’m wondering if you have any thoughts on best ways to keep pruners sharp and clean? I use rubbing alcohol to clean, but I noticed on a recent episode on cultivating that your guest used a lighter as well. Is fire necessary?
Thanks and keep up the great “work”/play!
Thanks Lesli!The fire is a sure way to kill any diseases on the blades. That and alcohol are a great combo. Others use 10% bleach solution mixed with water. That seems to work well also. Periodically, I also take my pruners apart and clean them with steel wool. Also lubricate with a touch of oil and sharpen the blade with a stone or device I get from the equipment company. There are lots of youtube videos on how to clean and sharpen pruners, especially the name brands like Felco.
I was wondering what you think about chopping the top leaving only 4-6 leaves of pepper plants I have been growing indoors since middle of February. I watched many popular gardeners on you tube discuss how bushy and prolific it makes them. I took a deep breath and cut them way back. I am holding my breath now to see what happens. I removed so many flowers and healthy leaves. YIKES!!! Do believe in this practice?
Great tips, one thing I also think is key is making sure they are sharpened as a clean cut is best. I saw a neighbor prune his shrubs with old dull pruners and it looked like spaghetti at the ends of cut branches! Aaaagh!
Being a newbie to gardening and plant care, information like this is extremely helpful. I recently came across another pruning article about azaleas and, apparently, I missed out taking advantage of some pruning last year that I should have done. This article reaffirmed that for me and brought to light some new information. Thanks Joe!
Couldn’t have come at a better time here in OK.
Going for the prune!
Thanks for the confidence!
Our home was resided and reroofed in the last two weeks. A lot of damage was done to our mature shrubs and I am particularly concerned about some Pieris, Azaleas, and Buford hollies. I have pruned the broken and damaged branches, but that has left them lopsided and awkward. If I prune more, I violate the one third rule. I would like to cut the Pieris way down if it would survive. What is your opinion?
Man, I hate when that happens. Could you cut branches back by 1/2 around the plants where needed to balance these out? The 1/3 rule is really more of a guideline. There are exceptions and now is a good time to go for it. You could also do this in two stages if you have the patience to make this a project you finish next year. It’s amazing how plants can recover and fill in quickly.
The Pieris can take a decent cutting back if you need to. That’s my opinion.
Great advice, thanks . I sure wish we could get your show in Burlington , NC. They stopped showing it on pbs a year ago or so & I don’t know why
Thanks Janet. I just checked the station finder on our website for Burlington, NC. We’re still airing. And we should always be on in NC, since UNCTV is our Presenting Station. Here’s the link to show you the upcoming lineup of our shows: https://www.growingagreenerworld.com/tv-stations-and-schedule/
Pruning terrifies me. I usually just bite the bullet and go at it and hope for the best. I love the show and am enjoying your blog posts as well.
Join the club Jeanetta. I think you’re in good company! It’s a big reason I wrote this resource. Sometimes we do get lucky when we go for it. But, if there were a better approach that could yield better results, and healthier plants, then why not, right?
Glad you love the show, and thanks for your comment.
Is there any reference material where I can find a complete list that tells when to prune different trees and shrubs?
Hi David. One of the best books I’ve seen on the subject is from my personal collection. The Pruner’s Bible; A step by step guide to pruning every plant in your garden, by Steve Bradley. It’s well illustrated and covers mostly shrubs. But it’s a great resource.
For trees, the most complete reference I’ve seen is out of the United Kingdom. The Pruning of Trees, Shrubs and Conifers (2nd edition) by George E. Brown, is comprehensive.
I’ll bet there are others.
And another guide to pruning I love is by Cass Turnbull. Appropriately titled: Cass Turnbull’s Guide to Pruning is a great resource to have in your library.
How about some advice on pruning dwarf citrus?
Thanks a lot. Like your site.
Dick