How To Prune A Crape Myrtle
***Scroll below to see crape myrtle pruning diagram
By: Brent Wilson - Wilson Bros Nursery
When it comes to pruning crape myrtles, it would be better to leave them alone than to prune them improperly. We've all seen over-pruning - people chop back crape myrtles below the knuckles each and every year.
When a crape myrtle is pruned back too far it has two effects:
- Reduces the number of blooms that will be produced during summer.
- New branches will grow far too long and therefore not be able to support the weight of heavy blooms - particularly when wet. These long branches weep over and often break off during heavy rains.
When a crape myrtle is pruned properly:
- It will produce twice the number of branches and therefore twice the number blooms as it did during the previous year.
- The new branches will be strong enough to support blooms.
The Time To Prune Crape Myrtles
Wrong-season pruning would mean November and December. Don't let "peer pressure" by neighbors and commercial gardening crews get to you. If you trim the crapes in the last two months of the year, and we get a warming trend in January or February, the trees might actually start putting on new growth. That new growth will be highly susceptible to freezing weather should it come on the heals of a warm spell. New growth will also tend to draw the cold right into the plant, causing needless damage to a tree that should be resting in dormancy.
So, the best time to trim crapes in is late winter or early spring - just prior to new growth emerging. For years, we've suggested this as a great time to trim them, because at that time we're also trimming back our roses and many other plants and trees.
Instructions for Pruning a Crape Myrtle
TOOLS NEEDED:
Due to customer demand, you can now purchase high quality pruning tools at Wilson Bros. new online gardening store: GardenerDirect.com
Figure A to the left is a drawing of a 4-year old crape myrtle tree as it may appear in late winter, when still in dormancy, and before new growth has begun to emerge. This tree has been properly pruned for 3 years and is ready to be pruned for the coming year. At the top of the branches you will notice seed pods that formed after last seasons blooms. In studying the diagram more closely you might notice where pruning cuts were made in previous years, and that wherever cuts were made two new branches emerged from beneath the cuts.
Figure B indicates where to make cuts when pruning your crape myrtle tree. The rule of thumb is to trace down from the top of a stem (from the seedpods if the tree bloomed), to where that stem meets a branch. Using a pair of sharp bypass or lopper pruners make a cut about 6 inches or so above the intersection - never below the intersection. The 6" stub that is left will be strong enough to support the new branches that emerge just below your cut. (Another method for pruning the top stems is to grap the top of the stem gently bending it over and make a cut where the stem begins to bend at the point closest to the intersection.) Repeat this process until all stems have been cut as is shown in Figure C below.
Figure C shows a crape myrtle that has been properly pruned. All top stems have been pruned to 6 inches or so above the intersection where the stem meets a branch. Two new stems will emerge from beneath your cuts. By using this method of pruning you will be promoting twice as many branches every season - which means a fuller canopy and twice as many blooms. To further "clean up" your crape myrtle tree, you can prune suckers that grew from the trunk base, and twiggy growth that emerged up and along the main trunk(s).
Corrective Pruning for Crape Myrtles
If you or someone else has pruned or sawed off a crape myrtle too far, such as shown in the photo below, it may be difficult if not impossible to restore to it's prior shape and form. However, there are ways you can prune from now on to re-create a nice shape and form.
In the image above this mature crape myrtle tree (12-15' height) was sawed down to 5 to 6' above the ground leaving unsightly 5" diameter stump caps. But, if this has been done, at least you still have 5' high trunks to start over with. If trunks have been sawed off to 2 or 3' above the ground it would have been better to cut them all the way to the ground - as when "rejuvenation" pruning.
So, if your mature crape myrtle has been cut back or sawed off too far, there might be two different ways for corrective pruning:
- Allow the branches to grow naturally to whatever height the first year. When pruning the following late winter or early spring you can top all of the branches at the same height several feet above the top of the sawed-off main trunks. This might extend the height of the canopy a few feet as new branches will grow from just beneath the cuts for next season. From this point on you could follow the pruning technique above.
-or-
- Allow the branches to grow naturally to whatever height this year. When pruning in late winter or early spring cut these branches to 6 inches or so above the sawed-off main trunks. This would not extend the height of the canopy. From this point on follow the technique in the diagram above; cutting 6 inches or so above where the cuts were made the previous year.
The image below is another example of how your crape myrtle should NOT look after pruning! This one was pruned to the knuckles.
Corrective pruning for a crape myrtle that has been pruned to the knuckles
Next pruning time, just don't prune branches all the way back to the knuckles. Instead, leave a 6" or so stub that will support the two new branches that emerge from beneath the cut.
Controversy
There is much controversy, even among "professionals" in the industry, as to the correct method for pruning crape myrtles. All I can say is that the Wilson brothers have been pruning crape myrtles since 1984 using the method described on this page. We've formed some exceptionally attractive trees with sturdy, well-shaped canopies that grow denser every year and produce an abundance of flower clusters.
Our Old Diagram
For those of you who liked our old diagram better we've left it on the page.
To print diagram below, right click on diagram and select "Print" or "Print Picture" from the drop-down menu
Other Crape Myrtle Pruning Tips
1. Sharp bypass hand pruners (pictured left) work fine for pruning younger crape myrtles with branch diameters of 1" or less. Due to customer demand, you can now purchase high quality pruning tools at Wilson Bros. new online gardening store: GardenerDirect.com
2. For older crape myrtles with branch diameters of over 1" in diameter, it may be necessary to use lopper pruners (pictured to right) for pruning. Older established crape myrtles that have developed a nice mature canopy and form do not necessarily need pruning on the canopy (top). However, you may have to prune suckers from the base and stray branches that spoil the shape of the tree. What is older? Maybe over 10 years in age. Due to customer demand, you can now purchase high quality pruning tools at Wilson Bros. new online gardening store: GardenerDirect.com
3. Suckers that grow from the base of the trunk of a crape myrtle tree can be removed any time of year.
SEE ALSO:
Planting A Tree
Insect Control For Trees
Choose from a category below to find pruning instructions for other types of Trees:
Choose from a category below to find pruning instructions for other types of Plants: