9 Pruning MISTAKES Most Homeowners Make

After 25 years in the green industry and a PhD in plant sciences, I can tell you one thing. The most common reason that plants fail in the residential landscape has nothing to do with soil, has nothing to do with watering, has nothing to do with plant selection. It comes down to a single tool, pruning shears. It's not that homeowners don't prune, it's that they prune the wrong way and oftentimes the damage is not obvious immediately. Sometimes it can take an entire season to see the damage, other times it takes years, but by then the plant is compromised, the structure is weakened, and the flowers are gone. Today I'm walking you through nine pruning mistakes I see most homeowners make. It's costing them their plants, it's costing them their blooms, and it's also costing them their money. Let's get into it. Mistake number one I see most often and it breaks my heart. Pruning spring flowering plants that actually bloom in the spring. If you have forsythia, lilac, wajillia, spireas, or azaleas in your landscape, and you're out there pruning in the spring, you're actually cutting off this year's blooms before they even have a chance to open. Here's why. These plants bloom on old wood, meaning that their flower buds were set last fall. When you prune in the spring, you're removing the wood that's actually going to flower for you. The correct way to prune these plants is immediately after you flower. That's your window. You prune then, then you have an entire growing season to produce new wood. That new wood is what's going to flower for you the following spring. Mistake number two is cutting into old wood on evergreens. This is the most permanent mistake that you can make, so let me be very precise here because this one matters. Arborvitae, boxwood, yew. Three of the most commonly pruned evergreens in the residential landscape. Here's what homeowners don't know. Once you cut past the green living foliage into the bare brown wood underneath, that branch will not grow back ever. The reason is simple. These evergreens, they do not produce new wood in the same way deciduous shrubs do. Once you've crossed that threshold, you have a permanent dead patch in your evergreen shrub. I've seen beautifully established arborvitae plants that have taken 15 years to establish get ruined in one afternoon with a pair of hedge trimmers. I always stay within the green zone when pruning evergreens. There's no recovering once you get past it. Number three is using dull or dirty tools to prune. I won't spend a lot of time here, but it does deserve to be on the list because it gets completely overlooked. Dull blades don't cut. They crush and they tear. And that crushed stem is an open invitation for pests and diseases to enter the plant. Clean cuts heal. Ragged cuts tend to linger. And here's the part that's even more important. If you're working through a landscape that has any disease pressure, and if you're using the same unsterilized blades on every plant, you're spreading that disease with every single cut. The fix is straightforward. Clean your pruning tools with rubbing alcohol after every use. Also, sharpening your pruning tools once every season. These two habits alone protect your landscape in ways that no pesticide can. If you're finding this video helpful, go ahead and hit the like button below. And if you haven't subscribed yet, consider doing so. I put out a video once a week based off of 25 years of real world experience. Now let's get back into it. Number four has to do more with trees than anything else. And that's cutting back to a collar and not leaving a stub. When you remove a branch, where you cut matters enormously. Every branch has what we call a branch collar. That's a slight swelling at the base where the branch meets the trunk of the main stem. That collar is where the plant's healing process begins. It's where the callus tissue forms and closes the wound off over time. When you leave a long stub cutting three, four inches away from the collar, the plant can't reach it. The stub dies, rots, and becomes a direct pathway for decay straight into the main structure of the plant. Something I hear often, and it's completely false, is that leaving a little bit of wood somehow protects the tree. But it doesn't. Cut clean, cut close to the collar, and let the plant do what it was designed to do. Mistake number five is removing one-third of the plant at once. This is the rule that most homeowners have never heard of, but every professional in the industry knows it. The one-third rule. Never remove more than one-third of a plant's total living mass in a single pruning session. Here's where things get interesting. A plant's leaves are its energy engine. This is where photosynthesis takes place. All the energy that a plant needs in order for its life cycle starts in the leaf. And when we prune too much, you push your plant into a stress response that it may take years to recover from. I understand the temptation, especially with overgrown shrubs where you want to take them back dramatically and all at once. But the right approach is to do it in stages over two or three seasons. It takes patience. Go too hard in one session and you may be looking at a plant that struggles for three or four years. Next is pruning excessively in the fall. And here's where things get interesting and where I push back on comments I see online and as well as some publications. Pruning stimulates growth. That is the basic biology of it. When you cut a plant back, the plant responds by pushing out new growth. Now, when does that become a serious problem? When you do it in the fall. New growth in the fall is soft, tender, and completely vulnerable to frost. You're pruning in September or October, triggering a flush of new growth. And then the first hard frost comes and kills exactly what the plant just spent its energy and resources producing. For most trees and shrubs, the correct pruning window is going to be late winter, just before the spring growth emerges, or in late spring after they flower. Fall is the one time of year you want to put your pruning shears down and leave things alone. Number seven is lion tailing trees. And this is most often done by well-meaning tree crews, but I occasionally see it done by homeowners as well. Lions tailing is when all the interior branches of a tree are stripped away, leaving foliage on the very tips of the limbs. It creates a tufted look like a lion's tail. It looks clean. It looks opened up. But structurally, it's one of the most damaging things you can do to a tree. Those long, bare limbs become lever arms in a wind event. They're prone to cracking and catastrophic failure. And the tree loses the interior branching structure that gives it its strength and its form. Proper canopy thinning removes the entire branch back to its origin. It does not remove the foliage from the interior of existing branches. If a crew offers to open up your tree by stripping the interior of the branches, just decline it. Mistake number nine is not sanitizing in between pruning, especially dealing with diseased plants. I touched on this with dull tools, but it deserves its very own entry because the consequences are severe and largely invisible until it's too late. If you have any disease pressure in your landscape, fire blight, phermopsis, leaf spot, photinia, et cetera, your pruning blades are a disease vector. One contaminated cut is all it takes to introduce that pathogen into a completely healthy plant elsewhere in your yard. The science backs it up. Pathogens travel on pruning tools. All it takes is 70% rubbing alcohol to rub down your pruners. It takes 10 seconds to do it. And it could potentially save your plants. This is a protocol that every professional landscaper work their salt does. And now I'm sharing it with you, the homeowner. So take the time and clean your pruners, especially if you know you have a diseased plant. So there you have it, nine pruning mistakes that I see homeowners make most often. The bottom line is this, pruning is one of the most powerful tools that homeowners have to take care of their plants when done correctly. It extends the life of your plant, maximizes their bloom production, strengthens their structure, and keeps your landscape healthy for decades. Done incorrectly, and it does the exact opposite. If you found this video helpful, please give it a like. It genuinely helps more people find this information that need it. And if you have a specific question about pruning, leave those down in the comments below. I'll do my best to answer those. Guys, as always, thank you for watching A Plant Doctor. And until next time, happy gardening.