If you’ve seen those crape myrtles with ugly knuckle-like stubs, butchered by overzealous improper pruning, you know what we mean by “crape murder.” Not only does this practice of topping trees make the tree look horrible, it makes it weaker and leads to problems down the road. Learn how to prune a crape myrtle tree in this blog. These flowering trees are worth the work!
The crape myrtle has a naturally majestic shape and a strikingly beautiful tree trunk. It requires full sun to perform at its best ability. Pruned correctly, the crape myrtle has a graceful elegance. Correctly pruned crapes have more flowers than those pruned incorrectly. Read more about Basic Pruning for Trees and Shrubs.
Indiscriminately whacking back a crape myrtle produces a thick, knobby stub of a stump from which sprouts a thicket of weak growth, whiplike shoots. The dense tangle of foliage thus created makes the tree more susceptible to diseases such as powdery mildew, and pests such as aphids and mites. When the bloom does come, many of the long thin shoots are too weak to hold the weight, and wind up hanging down in an unnatural mess. Sometimes they break off.
It looks even worse in winter when the poor bedraggled tree is leafless. Extreme shearing causes blooming to be delayed by six to eight weeks, a shortened bloom period, and fewer flowers overall. Crape myrtles trimmed annually to their knees will never display the beautiful multi-colored bark that gives the mature crape its outstanding winter interest that is every bit as desirable as the summertime flowers.
Crape Myrtle Myths
You may have heard that you need to remove a crape myrtle’s old seed heads or spent flowers to maximize blooming the following year. This is false.
You may have heard that since crape myrtles bloom on new growth (true enough), you need to remove old growth to maximize flowering and promote new growth. Not true.
You may think that hacking the tree back is the best way to keep it from getting too big for its location. This is not true either. You can reduce a crape myrtle’s size with carefully placed “thinning cuts”, as we describe below.
But maybe you planted the tree in the wrong place, or you selected a cultivar that gets too big for that location. Better to remove the tree that’s too big and replace it with one of the many dwarf varieties that naturally stay smaller. Perfect Plants offers ten different varieties of crape myrtle, with mature heights ranging from 8-15 feet (Tonto) to 25-30 feet (Natchez). Black Diamond Crape Myrtles are dwarf sized and stay between 8-10 feet tall and 8 feet wide at full size.
Read more about this in Instead of Over Pruning, Choose Small Trees to Fit Your Planting Site.
So, it’s time to prune crape myrtles correctly
You will need a pair of good quality hand pruners to clip branches up to one-half inch in diameter. Loppers are used for branches up to an inch and half thick. You may need a pruning saw for bigger branches and trunks. You may need a pole pruner with long handles for branches too high to reach with the loppers. These are the best tools to prune a crepe myrtle. You don’t need all of them… just do the best you can.
The best time to prune most trees is in late winter or early spring when they are leafless and you can clearly see the defining architecture. The crape myrtle is no exception to this rule.
Take a look at a tree, any tree. If you look closely you will see a swollen area where a branch joins a larger branch. This is the “branch collar” and it produces hormones that help to heal the wound from a severed branch. Make your “thinning cuts” to just barely above the branch collar, never flush with the larger branch, and never leaving a stub. Make “heading cuts” back to an outward facing bud or an outward facing side branch. Tree wound dressings are not helpful and can actually encourage decay.
The natural form (called the “growth habit”) of a crape myrtle is like a vase with multiple trunks, each with side branches fanning upward and outward, and no branches growing downward or inward.
Pruning a young crape myrtle tree:
During its first winter, you should begin training your new crape myrtle to the natural vase shape described above. Decide whether you want a single trunk or three to five evenly spaced trunks and remove all others at ground level. This (these) will be the main trunk(s) to be kept free of branches for three to eight feet (you decide), so that the crape’s beautiful mottled bark is exposed.
Select a few outward growing side branches above the chosen height on each main trunk, and remove those that are lower, inward growing toward the center of the tree, and those that are growing at unsightly horizontal angles. Side branches look best when they are growing up and out. Remember to cut back to the branch collar, and not flush with the larger branch, and don’t leave a stub. Cut off, or better yet, break off, all suckers that may be sprouting from the ground or base of the trunk(s). Cut out dead branches and the weaker of crossed branches.
If your new tree is whiplike with a single stem, use a heading cut a few feet above ground to encourage formation of shoots. The following winter select three to five of the new shoots to continue training for the vase shape.
How to fix a murdered crepe myrtle:
We can’t completely undo years of crape murder, but we can get the tree on the way to looking more like the fine specimen it was meant to be. How much can you prune a crape myrtles?
You don’t have to wait until winter for this first step:
- Cut off those ugly knobby stubs! Many new shoots will sprout from each of the stumps we just created.
- Next winter, select two or three of the strongest upright shoots on each stump, and cut off all the others. Cut back each of the selected shoots to about two feet long and just above an outward facing bud or outward growing side shoot if there is one.
- If there are more than five main trunks, cut the extras to the ground. We want three to five main trunks, each of which being clear of any side branches for three to eight feet above ground.
- If any of the main trunks is branched too low, remove the weaker branches and those that are growing inward. (Normally, we don’t prune out more than 25% of a tree at any one time, but this is major surgery and an exception to the rule.)
- Each winter thereafter, prune as described below. It can take up to five years or more to cure a murdered crape, but don’t give up.
Restoring a crape myrtle that hasn’t been pruned at all
Left unpruned, crape myrtles sometimes develop too many trunks, and always develop too many side branches. There is not enough air circulation for the trunk and branches to grow. Here we learn how to restore a crape to one with a single trunk or the more typical multi stem habit. Cutting back crape myrtles is essential for the health of the tree. It is never too late to prune your crape myrtles.
Choose one, three, or five (we like odd numbers!) of the strongest, straightest trunks and saw the others off at the ground. Unfortunately, this will encourage suckers to sprout up from the ground, and these should be removed as they appear.
Crape myrtles look best when the main trunks are smooth and clear of side branches for four to eight feet above ground, thus exposing the distinctive mottled and flaking bark that is so attractive. Remove all branches on the side up to the height that looks best for you.
If the tree is too large, you can cut off the tallest branches back to where they join another branch that is at least one-third as thick. This method, called a “thinning cut”, will preserve the natural shape of the tree while reducing its overall size.
If you have to remove an entire branch, cut it back to the branch collar. Remove a portion of a branch with a “heading cut” back to an outward facing bud or outward facing side branch. Do not remove more than 25% of the tree at one time.
How to Care for Crape Myrtle – Annual Maintenance
Cut off, or better yet, break off, all suckers that may be sprouting from the ground or base of the trunk(s). You can do this any time of year.
Each winter, cut out dead branches and the weaker of crossed branches. Cut out side branches that are growing inward toward the center of the tree, and those that are growing at unsightly horizontal angles, or pointing too far outward. Side branches look best when they are pointed up and out. Remember to cut back to the branch collar, and not flush with the larger branch, and not leaving a stub.
Over fertilizing crepe myrtle trees causes them to produce more basal suckers and make fewer flowers. Only fertilize your crape if a soil test indicates that one or more essential nutrients is in short supply.
Read more about crape myrtle care in our Crape Myrtle Grow Guide.