My crape myrtles have bloomed in the past but haven’t this year. The plants don’t show any signs of disease or distress. What could be wrong?
We don’t always know the reasons why plants bloom better some years than others. If you aren’t seeing any signs of disease or insect problem, finding the answer will require a bit of detective work.
Here are some of the most common reasons why crape myrtles don’t bloom:
Late Pruning: This is by far the most common reason for crape myrtle blooming problems. Crape myrtles should be pruned either after they finish blooming, or in very early spring before they sprout. Don’t prune them once they’ve started growing in spring, because those new shoots give rise to this year’s blooms.
Blooming can depend on variety.
Lack of Sun: Crape myrtles like around 6-8 hours of uninterrupted sunshine each day. If your plants only get a half-day of sun, or if they get shaded by a larger tree at some point during the day, they might not bloom as much as you’d like.
Drought: If the summer has been extremely dry, your crape myrtles may have gone dormant. With irrigation, or rainfall, they may bloom a little later in the season than usual.
Too Cool: Crape myrtles are heat loving plants. If you’ve had a cool, wet summer, or if you’re growing them at the northern edge of their hardiness zone, they may not bloom as much as they would in warmer climates.
Too Much Nitrogen: An excess of nitrogen fertilizer can cause crape myrtles to produce lots of leaves, but not many blooms. This can happen when crape myrtles are planted in the middle of a lawn that gets frequent feedings. Reduce the amount of nitrogen during the growing season, and feed your crape myrtles in spring with a balanced, slow-release organic fertilizer.
Shade can prevent blooming.
Not Enough Growth: Crape myrtles bloom on new growth, so if your plant is stunted for whatever reason (including the reasons listed here), it might not bloom this year.
Plant Variety: Some types of crape myrtles are more prolific bloomers than others, and some varieties bloom earlier or later than others.
Insects or Disease: Even if you don’t see an obvious problem, there may be an insect or disease affecting your crape myrtle blooming. Aphids, for example, can cause reduced blooming; and if your tree is tall, you’ll have a hard time seeing them.
Poor Drainage: Improper drainage and soggy soil can cause crape myrtles to be stunted or bloom poorly. Improving the drainage, or cutting back on irrigation, might help.
Blooms occur on new growth.
Planted Low: Crape myrtles should be planted with the root ball exactly at soil level. If they were planted too deep, or if they’ve settled, the roots may not be getting enough oxygen and the plant may not be draining water properly.
Spring Damage: Even if your crape myrtle looks good now, something may have happened earlier in the spring – such as a late freeze, disease, or insects – to damage this year’s blooming shoots.
Overgrown Roots: If you’ve corrected every other problem and crape myrtle still doesn’t bloom, you might try root pruning as a last resort. This practice is usually used on older, overgrown plants to jump-start growth and blooming.