Crepe myrtles are beloved for their bold flowers that can last for several months in the summer. So, realizing that yours isn’t putting out its yearly burst of color is a huge disappointment!
Most flowering issues can be traced back to environmental factors or improper care. But identifying the source of a specific flowering woe can require a bit more diagnostic know-how than the average gardener possesses.
Your Crepe Myrtle not blooming will undoubtedly set alarm bells ringing but before you go to the expense of calling in an Arborist, have a read of this article. It covers all the most common reasons this yard or garden favorite might not be flowering and how to fix it.
Reasons For Crepe Myrtle Trees Not Flowering
A Crepe myrtle that fails to bloom has typically been pruned too late, damaged by wind or frost, planted in the wrong location, or attacked by insects.
If some areas of your tree continue to appear healthy, while others are suffering, then there’s a very high chance that one of these factors is the problem.
Before jumping to conclusions, I recommend giving your specimen a good visual once-over. Look for signs of disease or poor health — not just on the buds and flowers but on the foliage, limbs, and trunk as well — that may be interfering with flower production.
The sooner such issues are addressed the better chance your tree has of making a full recovery.
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Pruning Too Late
Without a doubt, the most likely culprit for an otherwise healthy Crepe myrtle not blooming is that the tree was pruned too late.
This is because they flower on new growth only, which means the tree produces the current year’s flower buds after coming out of winter dormancy. If some or all of that new growth is pruned away in spring, flower production will be decimated.
When To Prune
In most areas, pruning should take place in February or March, well in advance of any new growth. Keep an eye on your local forecast to ensure that you have time to prune your Crepe myrtle before rising spring temperatures bring the tree out of dormancy.
Weather Damage
You may have timed your annual pruning perfectly, removing unwanted limbs well before your Crepe myrtle left winter dormancy. But Mother Nature can do significant damage of her own.
For example, an untimely spring freeze could kill off new growth and the associated flower buds. Or a bad storm could break off a large portion of your tree’s spring growth.
While weather damage can be disastrous for the current year’s flower output, it’s unlikely to have any long-term effects. The best thing to do is care for your tree as usual so that it is well-prepared for next year.
Not Enough Sunlight
If a Crepe myrtle continuously fails to put out an impressive summer bloom, then an environmental factor like lack of sunlight could be to blame.
As a rule, we gardeners tend to underestimate the amount of sunlight our plants need (and overestimate the hours of sun our landscapes receive). These are full-sun trees and require an average of at least 6 hours of direct sunlight per day.
Insufficient sunlight both decreases the number of flowers and causes those that do appear to be faded in color.
Pest Insect Damage
Few insects target Crepe myrtle flowers directly. The one notable exception is the Japanese beetle (Popillia japonica), which feeds on their flower petals as well as the foliage.
However, damage to other parts of the plant caused by aphids or other insects could impact flower production.
If your tree becomes infested in the spring or early summer, when buds typically emerge, it may opt to redirect energy to staying alive rather than producing flowers.
How To Get A Crepe Myrtle To Bloom
There’s no secret to getting a Crepe myrtle to flower. One that refuses to flower again and again is a clear sign something is wrong.
Meeting your tree’s environmental needs — e.g., water, sunlight, soil pH, and nutrition — will set the stage for consistent flowering each year. It’s also important to avoid mistakes like pruning too late in the spring to ensure new buds have a chance to open.
Frequency of Flowering
If you’ve noticed some Crepe myrtle trees in your area seem to bloom twice a year, you’re not imagining things! The second flush of flowers can be produced with a bit of strategic pruning.
After the first bloom and only when all of the original flowers have fallen off and been replaced with green seed pods, you can remove the ends with a pair of shears. This must be done before the seed pods turn brown.
Make your cuts below each cluster of seed pods, just above the leaf node. I recommend taking off as little growth as possible. Shaping and general maintenance pruning should still be reserved for springtime.
With any luck, your freshly pruned tree will put out brand-new flower buds where the cuts were made. So you can enjoy a second round of color with relatively little work.
Do Crepe Myrtles Bloom On Old Or New Wood?
All varieties of this species bloom exclusively on new wood that grows in the spring. Therefore knowing when to prune Crepe myrtle is so important if you want to get the most flowers from your trees.
Since they produce their flower buds immediately before they bloom, there’s no need to worry about harsh winters or summer drought killing off the next year’s flowers (as is the case with lilacs and many other ornamental trees and shrubs).
How Long Does Flowering Take
Most Crepe myrtle varieties begin blooming in late spring or early summer. In general, the closer to the equator you are (and the milder your winters) the earlier your tree will bloom.
Average bloom time can vary by 1 to 2 months, so don’t be alarmed if your neighbor’s trees begin flowering before your own.
Saplings may not bloom the first couple of years after planting. If they do flower, don’t be alarmed if the number of blooms is very low.
Flowers Not Opening
If your Crepe myrtle’s buds are slow to open yet the rest of the tree seems healthy, there’s a good chance you just need to be patient. Many environmental factors can cause a delay in flowering versus previous years, including unseasonable temperatures and drought.
With that said, unopened flower buds that are turning brown or drying up are not a good sign. The most likely culprits are nutritional imbalance, insects, or (in older varieties) powdery mildew.
According to UCCE Master Gardeners, excess nitrogen or a lack of phosphorus can sometimes manifest as flower buds that fail to open. I recommend testing the soil around your tree (take several samples in and around the drip line area) before ruling this out.
While insect damage or powdery mildew can certainly cause buds to die off, this is rarely the only symptom. Check your tree’s foliage for signs of disease and treat as necessary.
Regardless of the reason for a lack of blooms, or flowers failing to open, don’t panic. Failure to flower one year can be heartbreaking but doesn’t necessarily spell doom for the tree’s future.
When To Fertilize
Mature Crepe myrtle trees should be fertilized once per year in the spring. This ensures that the plant has all of the nutrients it needs to put out growth (including those much-anticipated flowers) throughout late spring and into summer.
Freshly planted trees may be fertilized throughout the growing season to build a strong foundation for future years. However, extra fertilization has little effect on flower production.
What Is The Best Fertilizer For Crape Myrtles?
When it comes to soil nutrition, these trees are extremely low-maintenance. When you choose a fertilizer for Crepe Myrtles be sure it does not contain excessive amounts of nitrogen. A well-balanced N-P-K ratio (such as 5-5-5 or 10-10-10) is best.
For even distribution, I always use a slow-release, granular fertilizer on my trees. I find this type of feed to be easier to distribute over the entire root system and provides the option of applying either by hand or by using a broadcast spreader.
The ideal soil pH for Crepe Myrle is between 6 and 6.5, so I suggest performing a general soil test around your trees before committing to a specific fertilizer. These trees require slightly acidic soil and anything beyond this pH range may inhibit your tree’s ability to absorb nutrients and prevent flower production.
Similarly, keep an eye on the amount of nitrogen in the soil. Excess nitrogen causes an overproduction of leaves and an underproduction of flowers.
