What’s Wrong With My Crepe Myrtle? 4 Common Problems

August 22, 2013 | By | Comments (134)
Crepe myrtle

Photo: Steve Bender

Crepe myrtles are for the most part trouble-free. That’s why lazy slobs like Grumpy like them so much. But certain problems do crop up in summer that make you want to pull out the magnifying glass and burn some ants. Here are some of the most common problems and what to do about them.

Problem #1 — Sooty Mold

Black mold

Yuck! Black mold on crepe myrtle. Photo: lsuagnenter.com.

Sooty mold is a fungus that covers the leaves and looks like you just sprayed your crepe myrtle with asphalt. (Note to reader: This is seldom a good idea.) The mold doesn’t feed on the foliage. Instead, it grows on sticky honeydew secreted by sucking insects like aphids, scales, and white flies that do feed on the leaves. Get rid of the bugs and black mold will go with them.

Solution: Spray your crepe myrtle according to label directions with insecticidal soap, horticultural oil, neem oil, or Natria Multi-Insect Control. All of these are safe, natural products available at home and garden centers.

Problem #2 — Powdery Mildew

Powdery mildew

Powdery mildew. Photo: aragriculture.org

The bizarrely cool, rainy summer we’ve experienced in the Southeast this year (sorry, everybody out west) means that if your crepe myrtle is susceptible to mildew, it probably has it. Powdery mildew is a filmy, white fungus that grows on leaves and flower buds. It causes leaves to curl and shrivel. Flower buds drop without opening. Back in the day when we didn’t have resistant selections, powdery mildew was the #1 complaint people had about crepe myrtles.

Solutions: Plant a mildew-resistant crepe myrtle. Almost all of the newer ones are resistant, including those named after tribes of native Americans, such as ‘Acoma,’ ‘Arapaho,’ ‘Catawba,’ ‘Comanche,’ ‘Miami,’ ‘Natchez,’ ‘Sioux,’ ‘Tonto,’ and ‘Zuni.’ ‘Dynamite,’ ‘Early Bird,’ ‘Pink Velour,’ and ‘Red Rocket’ resist it too. If yours isn’t resistant, spray the foliage according to label directions in early summer with neem oil, horticultural oil, Natria Disease Control, Daconil, or Immunox. The first three are natural products. You’ll probably have to spray more than once.

Problem #3 — Cercospora Leaf Spot

Cercospora leaf spot

Cercospora leaf spot. Photo: Steve Bender

Cercospora is a leaf spot fungus that used to be fairly uncommon, but isn’t anymore. Grumpy has a theory that the nearly universal planting of crepe myrtles in the South has made it easy for this fungus to spread. What happens is that in mid- to late summer, angular, brown spots form on the oldest leaves. These leaves then develop fall color prematurely and drop. By fall, the tree may be completely defoliated, except for a few newer leaves at the top. Fortunately, this seems to cause no ill effects the next year.

Solutions: This fungus likes sheltered areas where breezes are blocked and the foliage stays wet for long periods. Grumpy knows this, because the one he planted in front of his house gets eaten up by leaf spot every year, while the one growing in the middle of the lawn is hardly touched. Some websites claim certain selections are resistant, such as ‘Apalachee,’ ‘Catawba,’ ‘Sioux,’ ‘Tonto,’ ‘Tuscarora,’ ‘Tuskegee,’ and ‘Yuma.’ Grumpy has his doubts, because the one that gets devoured every year is ‘Sioux.’ What to do? Plant crepe myrtles in open, sunny spots where air circulates freely. If necessary, spray with Daconil, Immunox, or Natria Disease Control when spots begin to appear.

Problem #4 — No Blooms
No matter where you live in the South, crepe myrtles should have bloomed by now. If yours hasn’t, most likely it’s due to one of three reasons.

1. Your plant is just too small to bloom. Give it time.
2. Your plant isn’t getting enough sun. It likes full sun.
3. Some crepe myrtles bloom better than others. You may have a slacker. If so, replace it with one of the selections named above.

Attention: No ants were harmed in the production of this post.

COMMENTS

  1. Sylvia Wingate

    My crape myrtles have put on their leaves but right away they turn orange with black spots of them and then curl up. I’ve tried three different sprays , the last being Daconil because I read the spotting was a fungus. Nothing seems to help. Very few blooms ever and it seems that they bloom much later than other people’s crape myrtle. They are in full sun. Help!

    June 26, 2016 at 2:43 pm
  2. Susan Hebert

    Our crepe myrtle has not bloomed at all this year. It has a moss like spots on the trunk bark and main branches. The only change has been we removed bark and replaced it with river rock. My arbore says it is still alive. Could the rock be generating to much heat (we live SC)? Everyone else’s looks OK and healthly, but none have bloomed much this year. We don’t even have leaves. Suggestions/comments?

    June 25, 2016 at 2:27 pm
  3. Cara Carlson-Roberts

    My crêpe myrtle was planted about three months ago and has shown phenomenal growth! It does, however, have the brown spot fungus you mentioned above. Every day there are about three or four leaves that fall off in my hand and I dispose of them and so the plant seems to be incredibly healthy but hasn’t bloomed yet. It is about 5 feet tall and is supposed to be a red bloom. Should I be worried about this fungus. We had heavy rain in the spring but now it is hot and the plant gets about 14 hours of direct sun every day.

    June 22, 2016 at 5:12 pm
  4. Danna

    My crepe myrtle hasn’t bloomed this year, and the leaves are turning red and brown around the edges. It’s on the same watering system as usual and the bearded irises beneath it bloomed just fine. Any ideas what’s wrong?

    June 22, 2016 at 12:22 am
  5. Grumpy Gardener

    Ronald,

    Your plant has problem #2 above, powdery mildew. You can find all of the controls listed there at any garden center.

    Jose,

    Unless you had a hail storm recently, my guess is the culprit is Japanese beetle. Spray according to label directions with neem oil.

    June 21, 2016 at 1:52 pm
  6. Jose A. Honrado, Jr.

    my crepe myrtle leaves has lots of hole, almost the whole tree. what is causing this?

    June 20, 2016 at 4:36 pm
  7. Ronald Belluzzi

    i live in the bronx new york.I purchased a crepe myrtle from virgina beach 20+ years ago and it was barely a twig.It is now over 20 feet tall and blooms late june to september.I have never had a problem with it ever.Today i noticed a white powdery substance on the leaves.What is the best chemical to use that will not kill the grass or my dogs? Can you please tell me where i can purchase the chemical.That tree is my pride and joy it is a conversational piece at all my backyard events.Thank you.

    June 20, 2016 at 3:30 pm
  8. Steve Bender

    Lenora,

    If your crepe myrtle hasn’t leafed out by now, it’s not going to. Sorry.

    Nancy,

    Nothing better than bat guano to make a plant feel loved!

    May 30, 2016 at 9:27 am
  9. lenora

    Crepe Myrtles were trimmed in March.. There are no green healthy shoots, but little hard fuzzy ball looking things. Put the Bayer Tree and Shrub product around drip line. Other crepe myrtles in yard have branched out, however they are volunteers and much younger. the Natchez trees are over ten years old. Live in zone 8 of Southeast Louisiana.

    May 27, 2016 at 8:37 am
  10. Nancy Bradley Cromey

    Following strong language regarding my 5-year old crepe myrtle, which had not deigned to bloom, the tree finally, in year 6, put forth some effort. Not that the 7-8 mini-blossoms were spectacular, but we settled our differences with promises for this season. Also, it may be that a new red crepe myrtle planted close to the slacker encouraged an improved attitude – who knows? perhaps some existential reconsideration on the place of non-blooming trees in the greater scheme of things. Some application of bat guano may have helped too.

    May 26, 2016 at 4:14 pm
  11. Grumpy Gardener

    Betsy,

    If the damage is only minor, I’d live with it. Otherwise, try spraying according to label directions with neem oil.

    May 24, 2016 at 1:44 pm
  12. Betsy Oestreicher

    I live in way south Texas and planted a Crepe Myrtle tree 3 years ago. It has done very well,but recently I have noticed a cream colored bug about one-half inch in size eating on the leaves of it. How can I treat them?

    May 23, 2016 at 12:42 pm
  13. Grumpy Gardener

    Marilyn,

    The honeydew comes from sucking insects — probably aphids. Try spraying your plant with either horticultural oil or insecticidal soap.

    Evie,

    Spray them according to label directions with either neem oil or Natria Disease Control.

    May 20, 2016 at 2:04 pm
  14. marilyn needham

    what causes sticky leaves on my myrtle, which is in a greenhouse? can’t see any bugs. I’m in the UK

    May 20, 2016 at 9:24 am
  15. Evie Galbraith

    what can I do for powdery mildew on my crepe myrtle trees now?

    May 19, 2016 at 9:57 am
  16. KJones

    …just sent photos– thank you!

    May 13, 2016 at 3:48 pm
  17. Grumpy Gardener

    KJones,

    Is there any way to email me a photo? Send it to grumpygardenersl@gmail.com.

    May 13, 2016 at 1:17 pm
  18. KJones

    I live in Grand Prairie, TX. One of my crepe myrtles has had what appears to be leaf buds for several weeks. A few of them leafed out, but the leaves are about four times as large as the norm and they have odd shapes. If I didn’t know I would never guess it was a crape myrtle. My other two (different varieties) have fully leafed out and look normal.

    May 12, 2016 at 5:24 pm
  19. Grumpy Gardener

    Pam,

    How big are the branches that are falling off?

    Teresa,

    It sounds like your crepe myrtles has mealybugs or leafhoppers. Try spraying with neem oil.

    May 9, 2016 at 1:33 pm
  20. Pam

    New growth branches are falling off the trunk. There are no aphids on the leaves but the stem appears to have been chewed off.

    May 5, 2016 at 2:25 pm
  21. Teresa Strickland

    I’m in Texas. My crepe myrtle has little white balls on the tips of some leaves. Resembles fake snow. Any idea what this is?

    May 2, 2016 at 12:13 pm
  22. Grumpy Gardener

    Don,

    I have no experience growing crepe myrtle hydroponically, but think it would be much better off in the ground.

    Paula,

    Your crepes may indeed come back, but unless they have leaves there is no reason to water.

    April 25, 2016 at 2:46 pm
  23. Don D

    Have had dormant crape myrtle in a solution used supplier and when evaporated I changed to a light Miracle Grow and water solution…having been increasing the MG strength occasionally over past 3 to 4 months…to my surprise leaves are appearing on the trunk and they are growing and “multiplying”…now I have black tipped leaves at times and the blackness disappears when I do my occasional MG dose…three questions: has anyone else been able “hydrophonically” grow crape myrtles? If so, can they be planted in the ground or should I keep it the MG solution plus natural sunlight instead of Fluorescent Lighting? What could be causing the blackening of the leaf tips? I haven’t seen any bugs on the leaves.

    April 19, 2016 at 3:01 pm
  24. Paula

    My crape myrtles were nipped by a late frost and seem dead. They were just planted last year. Will they come back? I am watering heavily.

    April 16, 2016 at 12:18 pm
  25. Grumpy Gardener

    Mark,
    Crepe myrtle usually does’t bloom until June, so be patient.

    Claire,
    The green, fuzzy stuff are lichens. They are harmless.

    Kathryn,
    The long, unbranched shoots are called waterspouts. I would prune them off.

    April 5, 2016 at 9:56 am
  26. Mark Stowers

    If my 2 year old CM hasn’t bloomed or shown bud development by now (April), is it history?

    April 3, 2016 at 7:22 am
  27. Claire

    My crape Myrtle has green fuzzy stuff all over it. Really looks bad.

    January 27, 2016 at 10:14 am
  28. Kathryn King-Metters

    My crape myrtle has some branches shooting straight up from their branches. I rarely prune these as I like the natural growth best. What’s causing this? Should I prune these branches?

    November 21, 2015 at 11:39 am
  29. Steve Bender

    G. Prase,
    The leaves are about to fall off for the winter, so there’s no point in spraying anything now. Next spring, try treating them according to label directions with Bayer Advanced Tree & Shrub Insect Control.

    Oliver,
    Lichens are not the problem. They are harmless. Your crepe myrtles are suffering from something else. As their foliage thins out, they let more sunlight reach the branches, which is what lichens need to grow. The only thing I can suggest at this point is fertilizing your crepes next spring after they leaf out with a tree/shrub fertilizer.

    Susan,
    After your tree leafs out next spring, spray healthy foliage with one of the disease control mentioned above under problem #2.

    November 20, 2015 at 2:11 pm
  30. Oliver

    Just moved to this property in NW Fla.. Crepe Myrtles have lichens all over them barely bloom and seem to be struggling. What can I do. Oliver

    November 18, 2015 at 4:38 pm
  31. G.Prase

    My Crepe Myrtles have black Leaves and are infested with a reddish bug in the shape of a ladybug.I sprayed organic oil,soapy water.They left and came right back.It is very frustrating we like to see the pest be gone for good.

    November 11, 2015 at 3:59 pm
  32. susan mcbeth

    Mine has some kind of mold. Only one or two blooms. Yuk! brown spots on green leaves. New leaves at root are green, but spotted by the time they get grown up the branch. It is Sept. 19, 2015.. OK to cut back now. Is it dead for next year?

    September 19, 2015 at 2:00 pm
  33. Steve Bender

    Delicia,

    That is sooty mold. To get rid of it, follow the directions above.

    September 14, 2015 at 2:27 pm
  34. Delicia Dawn

    My Crepe Myrtles have black branches with white fuzz on them. I live in East Texas.

    September 14, 2015 at 12:44 pm

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