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

August 22, 2013 | By | Comments (99)
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. Teresa Blank

    For further information on my 40 + crepe myrtles. there are some areas that have rubbed deep and a green mold is appearing. How to I treat the mold what type of sprays. Malathion? Do I need to seal these areas to keep insects out?

    August 25, 2015 at 10:51 am
  2. Steve Bender

    Teresa,

    I have a large crepe myrtle that has done the same thing. I don’t think it poses any threat to the plant. You can remove one of the large rubbing branches, but you don’t need to.

    August 25, 2015 at 9:14 am
  3. Teresa Blank

    I have recently bought a home with a stand of crepe myrtles 9 large trunks. These trees are 35 – 40 years old. some of the branches have grown together at various places. However some branches are rubbing against other branches. this has caused breaks in the bark and in those areas it appears that it is ripe for infestation of bugs, ants etc. What should I do. I am debating to remove the branches and trunks that have been compromised. WHAT SHOULD I DO???????????????

    August 24, 2015 at 5:17 pm
  4. Steve Bender

    Nancy,

    Your tree may be suffering from the leaf spot described above or from hot, dry weather. It should recover.

    August 15, 2015 at 9:23 am
  5. Steve Bender

    Karen,

    I’m going to guess that this tree was root-bound in the pot when you planted it. When this happens, the roots stay in a solid ball and don’t spread out into the surrounding soil, making the plant susceptible to drought. After a while, it may grow out of this if you keep it watered. Or — if it’s still alive — you can dig it up after the leaves drop this fall and replant. Gently loosen the roots so they’re not tightly wrapped. Also, dig the hole no deeper than the root ball, but three times wider.

    August 15, 2015 at 9:20 am
  6. Steve Bender

    Jason,

    The pool work is definitely the culprit. The only thing I can recommend is that you flood the root zone of the crepe with water to wash out the accumulated chemicals.

    August 15, 2015 at 9:15 am
  7. Nancy Evans

    Problem: I have a crepe myrtle that has been with us three summers. It was growing nicely and had many blossoms a few weeks ago. Looked healthy. Now the new growth is dropping leaves and tree seems unhappy. Can you tell me what to do? Thanks, Nancy E

    August 11, 2015 at 9:50 am
  8. Karen

    I have a new multi trunk Crepe Myrtle. It was planted early April of this year. It WAS so healthy and tons of leaves. Slowly the leaves started turning brown and dry despite watering. The “tree guy” told me to just fill the “bowl” around the tree daily until established and that would be enough water. I looked up what you call Cercospora Leaf Spot, and it didn’t seem like this was it. I cut a small twig and it is still alive and green inside. Any ideas to help? Thank you in advance!! PS…I love you site!
    Karen

    August 3, 2015 at 7:38 pm
  9. Blue Griffon

    I spayed my Red Rocket with an antifungal and it seems to have worked though it dropped the infected leaves and new growth is appearing in their place. It is also starting to bloom. In much of what I’ve read about the Red Rocket, it is resistant to mildew once it gets established so I am waiting and watching for the next couple of years. If mildew still persists, I am changing to a Seven Sons Flower Tree as it blooms at the same time of year and deals with extreme heat without repercussions or perhaps another Forest Pansy Redbud or even a Rising Sun Redbud.

    I will also add that I have planted a Forest Pansy Redbud on the opposite side of my property, same exposure, and it is doing beautifully. The leaf color alone is more than worth the consideration and I am ecstatic about the look.

    To the person who’s Red Rocket is blooming pink; the first season of bloom in most of my trees and shrubs have been much lighter than advertised. My cherry was a silver white the first year, and my English Rose was pink. Give them one more year as the plant will adjust to the soil and probably be the color you expect.

    August 3, 2015 at 12:31 pm
  10. Jason

    I have 4 crepe myrtles, youngest prob 12 years old? The smallest one by my driveway and a shrub by it suddenly went from full bloom gorgeous to brown shriveled. Lost all blooms and all leaves are rust to light brown brown, like scorched.
    There are giant ginger plants a few feet away right on the driveway bed.

    The only change lately (its been 95-100 the last 3 weeks with no rain), is that we had our pool replastered. Our pool is just inside the driveway fence, behind the fence the crepe myrtle and other plants are in front of. They threw the drain hose out the drive, so no sure if chlorine water got into bed or yard, I saw most of it on street (even though I have a pump drain system-I hate contractors). But I don’t think they started browning/scorching until the last day of work when plastering. The mixing truck was parked just inside our gate, so the big mix area was right next to the gingers and myrtle and shrub. Tons of calcium and other chemicals in it I know. They also added a deck drain that was dug a few feet away from the myrtle through the front beds. But I didn’t see any roots slung out on lawn like they had to cut through any.
    Did my tree and others get poisoned? My ginger and holly bush just have browing on tips of leaves in areas, but the myrtle is brown as sand.

    How do I fix this? I read with chlorine poisoning on trees you keep watering to dilute it?

    When I break a tip of a branch, its green still inside, really green. But atrocious looking and honestly pisses me off to no end. I love my trees, only house in neighborhood with the front features like this. Everyone else is pine and cypress, or have one little accent myrtle.

    Thanks for any advice, in Houston, any and every guy with a chainsaw claims to be an arborist, and most plant stores don’t know jack except “buy our antifungal or pesticide”.

    August 3, 2015 at 10:14 am
  11. Steve Bender

    Mary,

    Follow the directions for controlling Cercospora leaf spot.

    July 29, 2015 at 2:09 pm
  12. Steve Bender

    Blue Griffon,

    What the nursery is telling you is pure B.S. None of that would cause mildew. However, the mildew is easy to control. Just spray your plant according to label directions with neem oil or Natria Disease Control.

    July 29, 2015 at 2:07 pm
  13. Steve Bender

    Lucy,

    Im afraid spraying is the only option other than replacing your trees with a selection that doesn’t get powdery mildew.

    July 29, 2015 at 2:05 pm
  14. Steve Bender

    Carole,

    Spray your plant with neem oil or horticultural oil.

    July 29, 2015 at 2:04 pm
  15. Steve Bender

    Richard,

    A lot of crepe myrtles are late blooming this year. Give yours some time. I’m guessing the green stuff is lichen, which is harmless.

    July 29, 2015 at 2:02 pm
  16. Steve Bender

    Becky,

    Spray your plant with either neem oil or horticultural oil.

    July 29, 2015 at 2:00 pm
  17. Steve Bender

    Debbie,

    Read the recommendations in the story about controlling sooty mold.

    July 29, 2015 at 1:58 pm
  18. Steve Bender

    Pat,

    A lot of crepe myrtles are blooming much later than normal this year. I think it’s the weather. Be patient. You can still get blooms.

    July 29, 2015 at 1:57 pm
  19. Steve Bender

    Dot,

    Spray your plant according to label directions with Natria Disease Control.

    July 29, 2015 at 1:56 pm
  20. Mary

    My crepe myrtle is new this year. $170 . It started blooming immediately and looked to love it’s new home. Then it suddenly looked as if it was in need of water and leaves looked dehydrated . I had wagered regularly. Now leaves are falling off starting under where bllooms were . Help

    July 22, 2015 at 2:12 pm
  21. Blue Griffon

    I’ve planted a Red Rocket Crape Myrtle, this year, in full sun, in southern exposure and am having a mildew problem. I called the nursery which I bought it from and they said it wasn’t a mildew problem but a fungus problem which said to me they just don’t want to be responsible for replacing it..

    The problem, they said was that the hole that it is planted in; 10″x72″, is not large enough to allow nutrients and air through the surface and that the salts underneath the concrete, added to the extreme heat concrete adds, was the cause of the fungus. I want to say “hogwash” about the whole thing but if anyone out there has some input for me I would appreciate it greatly. I’m not crazy about digging it up and growing it in a 7 gallons pot, as was suggested.

    July 20, 2015 at 1:03 pm
  22. Lucy Grasty

    my myrtle trees r too tall to spray so any suggestions on dealing with fungus problem??

    July 20, 2015 at 7:45 am
  23. Carole Gunderson

    The buds and some of the flowers of my CM are coated with a white moldy looking substance. There are also some spider webs on the end of some branches. What could it be.

    July 17, 2015 at 10:51 pm
  24. Richard

    My tightwad do not bloom where they are. The limbs have a light green spine growth on the limbs. What is it?

    July 14, 2015 at 12:28 pm
  25. Becky Meriwether

    my crape has sticky leaves with webs on some leaves

    July 12, 2015 at 5:42 pm
  26. debbie

    my crape murtle looks sick it hase black dots 0n it and sticky you turn the leafy over and it is full of tiney white dots then the leves turn a fall clore and fall off what should I do

    July 12, 2015 at 5:27 pm
  27. Brian Blanchard

    I have the leave spots and no blooms but the other 3 do, so I will try to treat it for spots. I will let you know how it goes. Oh I think it’s about a 20 year old one. Use to not be like this up to about 7 years ago. Now there is a pecan tree growing next to it maybe it’s blocking sun etc. I can send pictures ?

    July 12, 2015 at 11:34 am
  28. Pat

    Other than transplanting my CM, how can I get it to bloom? It’s very healthy, but not in morning sunshine. Major bummer.

    July 12, 2015 at 8:31 am
  29. Dot Morrow

    My Crepe Myrtle’s leaves are turning yellow with small green spots, then dying up and falling off. Help!

    July 10, 2015 at 1:52 pm
  30. Steve Bender

    DMS,

    It sounds to me like the start of Cercospora leaf spot. Spray now according to label directions with one of the fungicides mentioned in the story.

    July 9, 2015 at 3:08 pm
  31. Steve Bender

    Audrey,

    Sorry, but your tree is a goner. You’ll have to replace it.

    July 9, 2015 at 3:07 pm
  32. Steve Bender

    Cooper,

    I think your plants were mislabeled. Hope you kept the receipt.

    July 9, 2015 at 3:06 pm
  33. Steve Bender

    Barbara,

    This is absolutely normal and happens every summer.

    July 9, 2015 at 3:06 pm
  34. DMS

    I just planted my tonto crape myrtle in March, growing fantasticly, ready to bloom, however some of the leaves are red & yellow, doesn’t sound or look like the mold pictures, just look like fall colors to me. We’ve had a lot of rain this summer, could the leaves just be turning early?
    Thanks

    July 7, 2015 at 7:15 pm
  35. Audrey

    My crepe myrtle had fungus in the fall. We sprayed it. All the leaves fell of. It is now July and it is completely bare. Is this tree dead? What can I do to revive it?

    July 7, 2015 at 7:48 am
  36. barbara caillouette

    Two of my 15 year old crepe myrtles have lost their bark (like a snake) and the trucks are absolutely orange. Is this normal or are my trees sick?

    Barbara

    July 6, 2015 at 2:40 pm
  37. cooper88

    I ordered two Siren Red crape myrtles and planted them this spring. They are growing well, but they just started blooming light pink. Help!

    July 1, 2015 at 2:51 pm
  38. Steve Bender

    Fran,

    It is completely normal for the bark to start flaking off at this time of year. This is how a crepe myrtle grows — like a snake shedding its skin.

    July 1, 2015 at 1:06 pm
  39. Steve Bender

    Glenda,

    Yes, sooty mold can grow on the honeydew dripped onto branches by sucking insects. You can scrub it off using soapy water.

    July 1, 2015 at 1:05 pm
  40. Steve Bender

    Donna,

    A lot of readers have complained about the same thing. What happened is that a very cold winter severely damaged crepe myrtles or killed them to the ground. Now they’re growing back from the roots. They will not leaf out again at the top, so remove the dead trunks and branches. The shoots coming up will become the new trunks.

    July 1, 2015 at 1:03 pm
  41. Steve Bender

    Katelyn,

    This still sounds like aphids and black mold to me, so treat that as recommended.

    July 1, 2015 at 1:01 pm
  42. Fran Stone

    The bark on my 4 Crape Myrtles is peeling off? Is this normal? They all were very slow to bloom this year, but all of them finally blossomed.

    June 29, 2015 at 10:35 pm
  43. Glenda Taylor

    Can Sooty Mold get on the trunk/limbs of a Crepe Myrtle also? In late August last year the leaves turned blackish and fell off but the tree itself was (and still is a little) black. Will it die? How do I get the black mold off of the branches?

    June 28, 2015 at 10:16 pm
  44. Donna Woodford

    I planted 6 Natchez crepe myrtles in March of last year (2014) and they bloomed beautifully all summer. This spring the leaves took a long time to come out. One is blooming and the others have a few blooms but I had to prune a lot of dead branches out of them including main trunk stems. We had a late freeze (northwest Alabama) but I am not sure if they were budding then. Could that be the problem?

    June 27, 2015 at 2:43 pm
  45. Katelyn

    Mine have almost sticky black on the leaves and crystals (looks like salt) on the bottom of the leaves, not as black as the mold picture, and no blooms yet. They are larger trees but just planted this year (early early spring). What could be the problem?

    June 25, 2015 at 7:27 pm
  46. Steve Bender

    Vicki,

    Are there webs covering the ends of the branches? This sounds like the work of fall webworms. Try spraying those branches according to label directions with neem oil.

    June 25, 2015 at 1:27 pm
  47. Steve Bender

    Adina,

    My guess is the water from the sprinkler system isn’t reaching this tree any more. Maybe one of the sprinkler heads has stopped working. I’d also check to see if there is any damage to the trunks near the base.

    June 25, 2015 at 1:25 pm
  48. Vicki Endress

    My crape mytles bottom branches are covered with spider like webes. Is this healthy or not .It is 35 feet tall, so it is a bite to tall to spray the whole tree . What do I do ?

    June 23, 2015 at 7:04 pm
  49. adinahoshour

    Can anyone advise why my Natchez crape myrtle is displaying severe leaf wilt? I have two in the front yard with full sun exposure, but only one appears to be struggling and it has been in the ground for 5 years. Is it possible that it is receiving too much water from the sprinkler system or not enough water? The leaves are green, but wilted. The Japanese beetles are feasting away despite my having paid a lawn service to spray the tree. The temperature has been around 100 degrees…but none of my other trees are displaying this severe wilt.

    June 23, 2015 at 5:57 pm

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