How to Prune Crepe Myrtles

Crepe myrtles are stunning ornamental trees known for their colorful and crinkly flowers that bloom throughout the summer. With their peeling bark and graceful, arching branches, crepe myrtles make an excellent focal point in any landscape. However, to keep crepe myrtles looking their best and promote vigorous growth and ample blooms, proper pruning is essential. Pruning crepe myrtles may seem daunting, but following some key tips will have you pruning with confidence.

When to Prune Crepe Myrtles

The ideal time for pruning crepe myrtles is late winter to early spring, before new growth emerges. Pruning in winter when the tree is dormant avoids accidentally removing any developing flower buds for the coming season. It also gives the tree time to heal any wounds before spring growth starts.

While late winter is best, crepe myrtles are flexible. You can prune immediately after flowering finishes in summer to shape and contain growth. Just keep in mind this will remove next year’s flower buds. Moderate pruning is also fine in early fall but avoid heavy pruning after August.

Prune in Late Winter for Best Results

Prune in late winter, January to March, before new growth starts.
This avoids removing potential flower buds and gives wounds time to heal.
It’s the optimal time for shaping, thinning, and controlling size.

Summer Pruning Tradeoffs

Pruning right after summer flowering removes next year’s flower buds.
However, it lets you maintain shape and direct growth.
Use summer pruning judiciously for containment and minor shaping.

Moderate Fall Pruning

Some fall pruning before August is fine for minor shaping and thinning.
Avoid major fall pruning which stresses the tree going into winter.
Heavy fall pruning increases risk of winter damage.

With the right techniques and tools, pruning crepe myrtles is a straightforward process. Focus on improving shape, directing growth, and opening up the canopy to allow light and air circulation.

Follow these steps for pruning crepe myrtles successfully:

Gather Needed Equipment

Bypass hand pruners for smaller branches
Loppers for thicker branches up to 1 inch diameter
Telescoping pruner or pole saw for high reaching cuts
Disinfecting spray or wipes for tools
Tarps or sheets to collect fallen debris

Remove Suckers and Low Branches

Cut out any suckers growing straight up from the root system.
Remove low branches for most visual impact.
Aim for around 2 feet of clear trunk, adjusting for multi-trunk varieties.

Establish Good Branch Structure

Select 3-5 main branches spaced around the canopy to form a scaffold.
Remove competing inward facing branches to open up interior.
Make cuts just outside branching collars without leaving stubs.

Head Back Overly Long Branches

Locate long, lanky branches growing out of bounds.
Cut back by 1/3 to 1/2 to a side-facing bud or smaller lateral branch.
Direct growth outward and maintain desired size and shape.

Thin Inner Growth to Let Light In

Clear out congested inner branches to improve air circulation.
Remove smaller secondary branches growing toward the center.
Reduce disease risk and encourage blooms lower on branches.

Remove Dead, Damaged and Crossing Branches

Prune out any dead, diseased or broken branches back to healthy wood.
Take out branches rubbing or crossing to prevent damage.
Make clean cuts without leaving stubs.

Stand Back and Check Form

Step back periodically and check for any needed adjustments.
Balance the canopy and space branches evenly around the center.
Refine shape and direct growth using selective heading cuts.

Clean Up Debris

Drag tarps or sheets under the tree to collect fallen debris.
Remove all pruned branches and materials from the area when finished.
Disinfect tools before storing to prevent disease transmission.

Types of Crepe Myrtle Pruning Cuts

Knowing where and how to make proper pruning cuts is critical for maintaining tree health and encouraging blooms. Here are the main types of recommended pruning cuts for crepe myrtles:

Thinning Cuts

Remove entire branches back to the trunk, main branch or larger lateral.
Help open up interior, reduce density, improve sunlight penetration.
Ideal for removing suckers, competing inner branches and excessive growth.

Heading Cuts

Shorten over-extended branches back to a bud or smaller side branch.
Control size, shape growth and encourage branching and blooms lower on stems.
Make at an angle above an outward facing bud.

Reduction Cuts

Selectively cut back lateral branches to a smaller side shoot.
Maintain overall size and shape while reducing crown density.
Encourage new growth and blooms further down on branches.

Slant Cuts

Prune just outside the branch collar at a 45 degree downward angle.
Enable trees to seal wounds more effectively preventing decay.
Avoid leaving branch stubs which die back and create entry points for pests.

Pruning Mature Crepe Myrtles

Large, well-established crepe myrtles have some slightly different pruning needs and challenges compared to young trees. But with care and the right approach, you can rejuvenate overgrown specimens and maintain their beauty.

Rejuvenation Pruning

Start by removing up to one-third of oldest, tallest stems down to vigorous lateral shoots.
Can be done over consecutive years for full rejuvenation of neglected trees.
Encourages lush new growth and revitalizes blooms in dense, aging trees.

Multi-Trunk Varieties

Retain main trunks for structure but thin to highlight most attractive trunks.
Remove inward-growing branches to open up center.
Head back side branches evenly to balance growth around main trunks.

Scaffold Limb Renewal

Selectively remove 1-2 of the largest, oldest scaffold branches each year.
Cut back to lateral shoots or to the trunk for complete renewal over time.
Promotes new vigorous, productive scaffold branches to gradually reframe.

Safety Considerations

Use pole saws or chainsaws with care on mature trees. Have larger branches removed professionally if needed.
Prune symmetrically and avoid removing too much growth at once to prevent sunburn.
Monitor for decaying trunks and replace aging trees that could pose safety risks.

Problems to Avoid When Pruning

It’s important to follow proper pruning practices to keep crepe myrtles healthy and looking their best. Steer clear of these common pruning mistakes:

Excessive Hard Pruning

Removing too much growth stresses the tree and reduces flowering.
Can lead to sunburned trunks, suckering, and susceptibility to diseases.
Take out no more than 25% of living branches at one time.

Topping Trees

Cutting main leader stems back severely disfigures trees.
Causes extensive suckering and weak regrowth needing constant re-pruning.
Dramatically shortens bloom period. Never remove more than 1/3 height.

Pruning Too Late

Pruning in late summer removes developing flower buds for the next year.
Late fall pruning gives wounds little time to heal before winter, increasing decay risk.
Stick to pruning between late winter and early summer.

Poor Branch Selection

Removing too many lower branches leaves ugly stubs. Selectively head back instead.
Retaining inward facing branches creates congestion and blocks light penetration.
Make thinning cuts to establish evenly spaced scaffold branches.

Improper Cutting Technique

Leaving branch stubs invites insects/disease. Always prune back to the branch collar.
Avoid tearing and jagged cuts which harm the tree. Use sharp, clean tools.
Cut at an angle to allow water runoff and promote sealing.

How to Prune Young Crepe Myrtles

Young crepe myrtles in their first years after planting require careful pruning to establish proper form. Here are some key tips for pruning young trees:

Allow Time to Establish

Give newly planted trees 1-2 years after planting before extensive pruning.
Light thinning is fine but avoid heavy pruning which adds stress to establishing trees.

Select 3-5 Main Branches

Choose wide-angled branches evenly spaced around the trunk as permanent scaffold branches.
Remove competing inward facing branches to give them space to grow.

Find Apical Dominance

Determine the central leader stem with strongest apical dominance to keep as the leader.
Prune out other vigorous vertical shoots competing for height.

Set Proper Clearance

Gradually raise the canopy, removing lower branches over time.
Increase clearance to around 2 feet, adjusting for multi-trunk varieties.

Head Back Overly Long Branches

Locate long, flexible branches extending out of bounds.
Head back by 1/3 to 1/2 to an outward facing bud to direct growth.

Clean Cuts Only

Make all pruning cuts just outside the branch collar, no leaving stubs.
Use bypass hand pruners for smaller cuts to avoid tearing bark.

Prevent Heavy Pruning

Remove no more than 25% of branches at once on young trees.
Avoid overthinning interior and creating branch imbalance.

Pruning Crepe Myrtle Topiary Styles

In addition to pruning crepe myrtles into standard tree form, creative gardeners also prune them into beautiful topiary forms. Popular styles include:

Tree Form

Select a dominant central trunk to extend as a standard tree form.
Remove lower branches and head back upper branches to establish classic tree shape.

Multi-Trunk Form

Leave 3-7 main trunks and remove lower and interior branches.
Creates a small, ornamental tree with gracefully arching branches.

Crepe Myrtle Hedge

Plant shrub varieties closely and prune into a dense, continuous hedge.
Shear periodically to contain growth while allowing summer blooms.

Espalier

Train horizontal tiers of branches against structures in geometric patterns.
Provide strong support and prune regularly to maintain espalier shapes.

Pollarding

Cut trunks back to knuckles annually to induce rounded, ball-shaped heads.
Produces abundantly crinkly flowers on a condensed tree ideal for containers.

Topiary Shapes

Trim and train branches into ornamental shapes like spirals, cascades, and pom-poms.
Requires frequent shearing but makes a beautiful garden focal point.

Signs Your Crepe Myrtle Needs Pruning

To keep your crepe myrtles thriving, it’s important to monitor them and prune when needed. Watch for these signs it’s time to prune:

Overgrown, neglected trees with long, crossing branches.
Congested interior growth with poor sunlight penetration.
Suckers emerging from the base or root system.
Dead, damaged, or diseased branches.
Unruly growth getting outside intended shape and bounds.
Few flowers on interior old branches indicating the need for rejuvenation.
Unbalanced form requiring structural improvement and renewal pruning.

Paying attention to these cues and pruning accordingly will keep crepe myrtles shapely, vigorous and bountifully flowering season after season.

Frequently Asked Questions About Pruning Crepe Myrtles

When is the best time of year to prune crepe myrtles?

The optimal time to prune crepe myrtles is late winter, between January and March. Pruning while trees are dormant avoids removing flower buds for the coming summer and gives pruning wounds time to heal before new growth emerges in spring.

Should I deadhead spent crepe myrtle flowers?

Deadheading or removing faded crepe myrtle blooms is not necessary. The dried flower clusters can provide visual interest in winter. But some gardeners deadhead for a tidier look. Avoid deadheading after mid-summer when flower buds start forming for next year.

How much should I prune off a crepe myrtle?

Avoid pruning off more than 25-30% of the tree’s branches at one time to prevent stressing the plant. For general maintenance, remove around 10-15% annually. Rejuvenation pruning of neglected, overgrown trees can remove up to 1/3 of the oldest branches over a few years.

Can I trim my crepe myrtle in the summer?

While late winter is ideal, crepe myrtles tolerate summer pruning reasonably well. Light shaping and corrective pruning is fine after flowering ends. But avoid heavy pruning in summer which will remove next year’s flower buds.

How do I prune a crepe myrtle into a tree shape?

Select 3-5 main scaffold branches evenly spaced around the trunk to form the tree framework. Gradually remove lower branches over a few years to raise the canopy height. Head back upper branches and thin interior growth to establish a classic crepe myrtle tree shape.

Should you cut back crepe myrtles each year?

Crepe myrtles benefit from regular, annual pruning but avoid excessive thinning. Remove any dead or damaged branches annually. To maintain size and shape, selectively head back and thin older, overextended branches and congested areas about every 1-3 years.

What happens if you don’t prune crepe myrtles?

Neglected crepe myrtles can become overgrown and congested with reduced flowering. Dense interior growth shades out lower branches, directing energy to outer branches. Renewal pruning removing oldest branches rejuvenates overgrown plants. But annual light pruning is better than no pruning.

Conclusion

While pruning crepe myrtles may seem daunting at first, having the right tips and techniques makes the job much easier. By pruning crepe myrtles at the optimal times, using proper cutting methods, and avoiding common mistakes, you can maintain beautiful, healthy, prolific flowering trees. Pay attention to your trees’ needs and prune as required to direct growth, improve shape, open up interiors, and encourage abundant blooms. With the right approach to pruning, crepe myrtles will flourish and enhance your landscape for years to come.