Knowing how to prune crepe myrtles is one of the most important skills for keeping these beautiful trees healthy and blooming their best. Done correctly, pruning encourages stunning summer flowers, improves the tree’s shape, and prevents common problems. But done wrong, it can lead to weak growth and fewer blooms. This guide will walk you through expert techniques to get it right every time.
How to Prune Crepe Myrtles
Pruning crepe myrtles isn’t about heavy-handed cutting. It’s a thoughtful process of selective removal. The main goals are to open up the canopy for light and air, remove crossing or damaged branches, and encourage the growth of strong new stems that will produce flowers. Forget the severe topping often called “crepe murder”; that practice harms the tree’s natural structure.
When is the Best Time to Prune?
Timing is crucial for success. The ideal window is in late winter, when the tree is completely dormant. This is usually in February or early March, before new leaves begin to emerge.
- Why Late Winter? Pruning at this time means the tree can put all its energy into spring growth. It also allows you to clearly see the branch structure without leaves in the way.
- Avoid Fall Pruning: Cutting in autumn can stimulate new growth that will be killed by frost, wasting the tree’s resources.
- Light Summer Pruning: You can do light trimming in summer to remove spent flower clusters, which may encourage a second bloom.
Essential Tools You’ll Need
Using the right, sharp tools makes the job easier and prevents damage to the tree. Here’s what you should have on hand:
- Hand Pruners (Bypass Style): For small twigs and branches up to ½ inch thick.
- Loppers: For branches between ½ inch and 1½ inches in diameter. Their long handles provide leverage.
- Pruning Saw: For any larger branches, usually over 1½ inches. A curved saw works well.
- Safety Gear: Always wear protective gloves and safety glasses.
Remember to disinfect your tools with rubbing alcohol before you start, especially if you’ve used them on other plants. This helps prevent the spread of disease.
Step-by-Step Pruning Guide
Follow these steps in order for a healthy, well-shaped tree.
Step 1: Remove Suckers and Basal Sprouts
Start at the bottom. Look for thin, whip-like shoots growing from the base of the trunk or roots. These are called suckers. Also remove any small sprouts growing low on the main trunks. They divert energy and give the tree a cluttered look.
Step 2: Clear Out the Interior
Look inside the canopy for branches that are growing inward toward the center of the tree. Also identify any branches that are rubbing against each other or that are crossing. Remove the weaker of any two crossing branches. This opens up the tree’s center, improving air circulation and reducing disease risk.
Step 3: Address the Main Trunks and Structure
For a multi-trunk tree, choose 3 to 5 strong, well-spaced main trunks. Remove any others at ground level. On all trunks, carefully cut off any side branches that are growing back toward the center. Also remove branches that are smaller than the diameter of a pencil from the lower third to half of the trunk. This creates a clean, attractive trunk line.
Step 4: Trim the Tops for Flowers
Now, focus on the tips where flowering happens. Locate last year’s seed pods (the small, brown clusters). Follow the branch down to the first set of healthy, outward-facing buds or a side branch that is at least as thick as a pencil. Make your cut about ¼ inch above that bud or branch. This is where new flowering shoots will grow from. Avoid just cutting everything back to the same height; instead, prune to varying heights for a more natural shape.
Common Mistakes to Avoid
- Topping (“Crepe Murder”): This is the worst mistake. It involves chopping all branches back to thick knobs. It causes weak, spindly growth, larger but fewer flower clusters, and makes the tree more susceptible to disease and insects.
- Pruning Too Late: If you prune in spring after leaves appear, you’ll remove the flower buds that formed on new growth and significantly reduce blooming.
- Over-thinning: Removing to many interior branches can leave the tree looking sparse and unnatural. The goal is to open it up, not strip it bare.
- Making Flush Cuts: Always cut just outside the branch collar (the slight swelling where the branch meets the trunk). Flush cuts damage the tree’s natural healing zone.
Pruning Young vs. Established Trees
Your approach should vary with the tree’s age.
Young Trees (First 3 Years): Focus on establishing a good structure. Choose your main trunks and remove competing leaders. Prune lightly to encourage branching, but avoid heavy cutting. The goal is to build a strong framework.
Established Trees: Follow the step-by-step guide above for maintenance. The focus shifts to removing problem branches, thinning for light, and tip-pruning for blooms. Never take off more than one-third of the total canopy in a single year.
FAQ: Your Crepe Myrtle Pruning Questions Answered
Q: Can I prune my crepe myrtle in the summer?
A: You can do light pruning in summer to deadhead spent flowers, which might prompt a second bloom. But major shaping or size reduction should always be done in late winter.
Q: My tree was topped by a previous owner. How can I fix it?
A: It will take a few years. Choose 3-5 of the strongest new sprouts from each knob to become new main branches. Remove all the others. Each winter, prune these new leaders properly, as described in Step 4, to encourage strength. Eventually, you can remove the old knobby tops.
Q: How do I prune a crepe myrtle that’s too tall?
A> Reduce height gradually over 2-3 seasons. Each winter, identify the main branches causing the excess height. Prune them back to a side branch that is growing in a more horizontal direction. This is more effective than just cutting the tops off vertically.
Q: Is it necessary to prune crepe myrtles every year?
A> While an annual late-winter pruning is recommended for best flowering and form, a missed year isn’t a disaster. Just avoid letting multiple years go by without any pruning, as the tree can become dense and congested, which effects flower production.
Q: What do I do with the pruning wounds?
A> Do not use wound paint or sealant. Trees heal best on their own. A proper cut just outside the branch collar allows the tree to compartmentalize the wound naturally. Sealants can trap moisture and promote decay.
By following these expert techniques, you’ll have a crepe myrtle that is not only a stunning focal point in your summer garden but also a healthier, stronger tree for years to come. The key is patience, good timing, and making thoughtful cuts that work with the tree’s natural growth habit.