“What caused my grown crepe myrtle to die? it was doing fine for many years, then just died. I cut down the branches [last spring] hoping it would revive, but it did not. I have several crepe mytles and never had one die before. Question from Sandy of Wake Forest, North Carolina
Answer: Crape myrtles (Lagerstroemia indica) are usually quite trouble-free, but there are some threats that can cause them serious problems. Cold snaps will certainly cause crape myrtles to die back to the ground, but I see that your winter weather last year was quite mild.
Crape Myrtle Bark Scale
Another possibility for the fast decline of your trees is the crape myrtle bark scale (Eriococcus lagerstroemia or CMBS). The serious pest just recently appeared in North Carolina (click here for a detailed fact sheet), and it can devastate trees. SMBS is a fuzzy white scale insect that quickly covers crepe myrtle branches, sucking the life out of the newer and older growth. Live scale insects can be squashed in the summertime to reveal their red, blood-like interior. It’s a good way to identify the pests. Various external and systemic pesticides can be used to kill CMBS. To learn more, please contact your local extension agent (click here to find your local extension agent).
Most other crape myrtle pests and diseases cause limited damage, so make sure your trees are fully dead before cutting them down. Were any of last year’s leaves and stems alive? If so, continue to prune off the dead stems next season, leave the living stems, and contact your extension agent as soon as possible. They can test trees for the presence of additional diseases that may be plaguing them.
Black Gold Horticulturist
“My crepe myrtles don’t bloom. I’ve added “blossom booster,” but still no blooms. Any suggestions?” Question from Carol of Douglasville, Georgia
Answer: How frustrating! You plant one of these glorious flowering shrubs/trees and…no flowers. There are a few possible reasons why yours won’t bloom for you.
- Light – One of the most common reasons is too little light. Crepe myrtles (Lagerstroemia indica) are sun lovers that need high light to bloom well. If yours gets a good bit of shade, little to no blooming can result.
- Food and Soil – Well-drained soil enriched with organic matter (peat moss or compost) will also encourage good growth and blooming. Fertilizer is also important. I would choose a slow-release fertilizer formulated for flowering. Work it in around the root zone at the beginning of each season.
- Heat and Water – Parched summers that are extra hot can put a strain on these plants and reduce flowering. Does yours look otherwise healthy? If not, I would provide it with additional water when the summer weather is at its worst. Likewise, prolonged excess moisture can cause poor growth and root rot.
- Disease – Several crepe myrtle diseases can put a damper on health and flowering. Powdery mildew, which appears like a whitish powdery dust on leaf surfaces, stresses plants and negatively impacts flowering. Likewise, Cercospora leaf spot, which results in spotty leaves that fall prematurely, can reduce flowering. If you suspect mildew, look into the effective fungicide, GreenCure. For leaf spot, try a copper-based fungicide spray. To reduce the impact of both diseases, prune out dense, internal branches to encourage airflow, and be sure to clean up fallen leaves in autumn.
- Variety – Consider the variety. Some are more reliable than others. If yours just won’t flower well, then choose a tough, reliable variety with excellent flowering performance. I recommend three vigorous, disease-resistant varieties: the deep-red flowered Dynamite®, brilliant pink ‘Hopi’ and lavender-violet ‘Zuni’.
I also recommend that you contact your local UGA Extension Agent to get more tips for your growing area.
Black Gold Horticulturist