May 12, 2018
Do you know of any way other than continually snipping, to get rid of crepe myrtle suckers? I tried just letting some of them grow to branches, but that will take forever and looked so bad I finally cut them. Do you think I could Put Round Up on some of the suckers without killing the entire plant?
Some varieties of crape myrtles will sucker every year for their entire lives, while others don’t produce any suckers. If you have a suckering variety, cutting out the suckers right beneath the soil surface once or twice a season should suffice. I would not recommend using Roundup as the suckers are attached to the mother plant and you could cause damage.
May 5, 2018
My wife and I have been to your classes so we know not to “murder”our crape myrtles. I keep them fertilized and pest free - 2 weeks before the frost they were coming out beautifully but the frost killed all the leaves and they aren’t coming back out - what can I do, if anything?.
I think you just need to be patient. I cannot imagine that you got cold enough in Hot Springs to actually kill the crape myrtles. They got nipped, and then we had cool temperatures for a bit after the frost. Now that we are getting up in the upper 70’s low 80’s I think you should see some rebounding soon. Once you see some new foliage appearing, give them a little fertilizer to speed them along. In a worst case scenario, they may have a little top kill but will still sprout out.
April 28, 2018
The April 7 freeze looks like it killed the bright red 1-2" new growth on my crape myrtles in
Benton. How much will this set back new growth? When can I expect to see any new
growth? Thank you.
The cold weather caused many plants to get nipped, some worse than others. I think here in central Arkansas the plants should already be rebounding. If you don’t see it now, after a few more warm, sunny days you should see new leaves beginning to pop. We were already having a late spring, so it will delay the first blooms by a bit, but not by much.
February 24, 2018
I just trimmed my crape myrtle and I'm afraid I may have committed an act of crape murder. I just wanted to get it down to the height I could treat for this bark scale thing. The tree is only a couple of years old and it's going to be taller than I really want. I'm thinking about replacing it. Have any resistant varieties been identified?
At this time, we do not have any varieties that are known to be resistant to the crape myrtle bark scale, but there is ongoing research to try to determine if there is any difference in varieties and their susceptibility. We will share the findings once we have them. We do have an excellent database of crape myrtles by size—you may want to pick a variety that fits your height requirements to avoid future crape murder. https://uaex.edu/yard-garden/resource-library/crape-myrtle/
November 25, 2017
We have several Crepe Myrtles in our yard that are not doing well & appear to have dark “mold” on them. What do they need?
This is becoming one of the most frequently asked questions in Arkansas. Prior to the arrival of the crape myrtle bark scale insect, we considered crape myrtles fairly bulletproof. Occasionally a variety would be susceptible to powdery mildew or aphids would attack, but many gardeners planted crape myrtles and just forgot about them. Now that the leaves are falling off the trees we are seeing even more clearly the black stems and trunks of many crape myrtles which is an indication that they have a case of the crape myrtle bark scale. These insects feed on the trunks of the trees. If you look closely you will see the white felt-covered insects. As they feed, they give off a sticky substance called honeydew. It is on that substance that the black sooty mold forms. The insects multiply rapidly during the growing season and a heavy infestation makes the trees look unsightly with the black covering, but they can also weaken the trees and impact blooming. If your trees are infested, use a soft brush and soapy water and clean the trunks now. Then spray thoroughly with a dormant oil. This will give you a good start on control, but unfortunately usually doesn’t give total control. Crape myrtles have peeling bark as they age, and the insects can protect themselves from contact sprays by getting up under the bark. Next spring, use a systemic insecticide and you should get good control of the problem. This is a relatively new insect for gardeners across the south, and researchers are working on other biological controls and options. We will share as we get them.
November 18, 2017
Now that the leaves have fallen, is there anything we should do to our scale-infested crape myrtles? I have never "murdered" mine, and don't want to, but they sure were ugly with black leaves. I was afraid if I cut them back, they'd just get re-infested in the spring anyway, and then I would have ruined the shape. Can this scale kill the trees, or will it just make them look awful?
Now that the leaves have fallen, you can take a soft brush with warm, soapy water and clean the trunks to remove the black sooty mold. Then spray with a dormant oil, saturating as much of the tree as possible. Dormant oil smothers out the scale insects they come in contact with, but keep in mind that crape myrtles have peeling bark where scale insects can hide. Next year in March or April apply a systemic insecticide. We don’t think the scale insects will kill a crape myrtle but they can keep them from blooming well. They can also weaken the tree where something else could attack.
October 7, 2017
We moved back to Little Rock in April. The landscaping had suffered some neglect because the house had been vacant for a few months. The Crape Myrtle pictured looks like it might not survive. We're not sure if it is due to under watering during the months he house was vacant, or if it's diseased. We'd appreciate your input and suggestions.
From the picture I cannot see any signs of the crape myrtle bark scale, nor do I think it looks like it is on death’s door. Many plants right now from trees and shrubs to perennials are looking peaked from lack of water. I would get it through until February and then prune it back some from the top and thin it out a bit to build more structure. I typically prefer 3 or 5 main trunks, and then take out anything that is smaller than a pencil in diameter. Monitor its growth next spring and see how it leafs out.
September 30, 2017
Is it too late for me to trim crape myrtles and red top photinias? I also have some large woody plants that are growing around my back yard that I have cut back but they just seem to be doing better than ever. I have heard that you put salt on them to kill them. Is it rock salt, how do you do it without killing everything around it?
The time to prune crape myrtles is in February, before new growth begins. Pruning them in the fall can expose them to winter damage if we have a cold winter. The key is to get them through the bulk of the winter before pruning. If your red top photinia just needs a light trim, that is fine to do now, but severe pruning--removing more than 1/3 of the plant should be done in the spring; you don’t want to encourage too much new growth this late in the season. I do not like to use salt to kill plants, as salt will stay in the soil for a long time and can leach out and damage nearby root systems. Once you cut the trees down, you can paint the stumps with an herbicide such as Brush-B-Gon, Brush Killer or Roundup Super Concentrate. Monitor these trees next spring as new growth begins, and if you see new growth repeat the above process.
August 26, 2017
I have just recently been seeing something on our crape myrtles that I've never seen before. Can you please tell me: what is this white fuzzy stuff? Is it harmful, and, most importantly, how do I get rid of it? Thanks so very much!
It is powdery mildew, a common fungal disease of crape myrtles. The frequent rains and high humidity have made it worse this late in the season. Some varieties are more susceptible than others, but from the photo it looks like your foliage is fairly clean. I would deadhead—cut off the infected blooms and see if you might not get another set of flowers that are not affected. I would not advise spraying this late in the season.
August 12, 2017
I have an out of control "shrub" that is made from runners off a tall crape myrtle. Cutting it back only seems to exacerbate the problem. How can I get it under control?
It sounds like you have root suckers coming up. If possible cut the sprouts right below the ground line. Some varieties sucker more than others, but typically it is just at the base of the tree—it sounds like yours are moving a bit further away. Herbicides would damage the mother tree as well as the sprouts, so avoid those.
July 1, 2017
Is this a butterfly bush? Can you identify?
No it is not a butterfly bush but a young or small crape myrtle.
June 17, 2017
I have six crape myrtles that are about ten to twelve feet tall, and have bloomed for the last five years. This year one has lots of blooms and the others have none. They are green and healthy looking. Do some bloom at different times? I don't remember them doing that, but maybe I did not pay close attention.
There can be some variability to blooming of crape myrtles based on variety, amount of sunlight they receive, age of the tree, and how much or little they were pruned. If they are getting at least 8 hours of sunlight a day, they should bloom. I would also check for any possible crape myrtle bark scale damage on the trunks. We have found that a heavy infestation does impact blooming.
May 20, 2017
I have 5 single trunk crepe myrtles that planted in 2009. The trees are all healthy and have developed beautiful thick trunks. They have never been pruned and are now over 20' tall. I know they are overdue for a good prune. When is the optimal time and how far down should I go? Their blooming hasn't been great due to the larger oaks around but I'm sure they could look better. I prefer a high fairly dense crown.
I do like the look of a single-trunked crape myrtle as well as the multi-trunked versions. The time to do any pruning would be in late February through early March. If you prune this late you will remove potential blooms or delay flowering. How much you take off would be based on what you are looking for. I normally don’t recommend taking off more than 1/3, but if there is room for them to grow tall, possibly just a little thinning may be all that is needed. Definitely keep those beautiful large trunks intact. Blooming is always best on crape myrtles in full sun.
April 15, 2017
If you have big knots on crape myrtles from previous prunings, can you prune below the knots and will the plants be OK?
You can prune below the knots or choose three of the biggest sprouts coming from the knots and prune out everything else. If you do prune below the knots, as they begin to sprout out, again, selectively limit how many sprouts you leave. While pruning this late is not going to kill your plants, it will delay the first blooms. Most crape myrtles are fully leafed out by now. You might do a third of the knobs this year and tackle the rest next February.
March 11, 2017
My wife and I enjoy your column. Recently I was rereading one of your articles in the NW Arkansas Democrat-Gazette about treating crape myrtle trees infested with the invasive bark scale insect. You advised pruning heavily infested branches and said that burning would be the preferred disposition, but that you cannot burn refuse in city limits. That is certainly not true in Fayetteville, unless it's so dry that a burn ban is in effect. I just call the fire department and give them my address. They used to issue permits, but no longer do that, just give permission. Perhaps your statement is true in Little Rock, but I'll bet the local authorities would have no problem with a small fire to get rid of infested yard waste if the circumstances were explained. The double bagging you recommended is cumbersome and not effective if the branches poke holes in the bags.
A good point--double bagging a lot of refuse is not easy. I think your recommendation to check with your local fire department is a great idea. The key is to ask permission, not forgiveness!
February 25, 2017
I read your article on the scale problem in the LR area. I have heavy infestation of my Crape Myrtles and my Privet bushes. I tried to wash the scale and the mold off with soapy water. It was very difficult and slow going. I then used my electric pressure washer (1600 psi) and it cleaned the trunks and branches in no time and it was much easier. The bark seems very clean with no sigh of damage. Next, weather permitting, I will treat with dormant oil and then the systemic insecticide.
Great idea, just make sure when using the pressure washer that it is not too intense to cause damage to the trunks
September 24, 2016
My husband is very cautious about planting trees and large shrubs too close to the house because of roots. I planted a crape myrtle bush right in front of our large picture window on my own years ago (picture included). Now that it is getting bigger, my husband is talking about pulling it up because he's concerned about it being too close to the house. I do not want it moved! I see crape myrtles planted right in front of people's houses everywhere in our surrounding area. Is this indeed going to be a problem?
I am not concerned with the roots interfering with the house, but I don’t think it is in a good location. The crape myrtle will continue to grow larger and it is covering up your window. I think it would have so much more potential if you moved it to a location where it had room to grow and bloom.
September 17, 2016
We have three very large approximately 25 ft. tall crape myrtles lining our drive way. They are very messy constantly dropping flowers on our cars. I would like to know if there is a time of year to prune so they won't bloom. If I cut them back to about 3 feet what will happen? .
I believe this is a first! Most people want to know why their trees are not blooming, or how to make them bloom better, but I have never been asked how to make them stop blooming. The reason for planting crape myrtles is to enjoy the flowers. Crape myrtles bloom on the new growth, so even pruning them hard will still allow them to set flowers, but you will typically have weeping crape myrtles which may actually have branches hitting your cars, depending on how close to the drive they are planted. If you really don’t want blooms, watch for them to begin to set buds, and prune in late June or July. You could also plant some other trees to provide shade-crape myrtles don’t bloom in the shade. If it were me, I would enjoy the blooms.
September 10, 2016
I have three crepe myrtle trees. One has no suckers, one tree has a few suckers, and the tree in my front yard has so many suckers I can hardly keep up with cutting them down each week. It looks like a small forest around the base of the tree. Are there any alternatives to physically cutting off the suckers such as a spray or other chemical application? I am exhausted.
Some varieties of crape myrtles sucker more than others as you have found out. Chemical controls won’t work, as they could hurt the mother plant as well. Try getting to the suckers early in the summer when they first get started, and try cutting slightly beneath the soil line. Then mulch around and see if that hinders them a bit.
August 13, 2016
When is best time to cut back Crape myrtle?
Crape myrtles are pruned in late February to mid-March, before new growth begins.
July 9, 2016
Could you send me the info on the 'white' mold that is one the crepe myrtles this year? I know you wrote about it earlier this spring. What is the treatment if any?
Since you are in Bella Vista I would guess you have powdery mildew, a white powdery substance that covers the leaves, and not the white felt scale which those of us in central Arkansas are seeing everywhere which gets on the branch and trunk. I have seen some trees heavily covered in the powdery mildew, so it is bad this year too. Use a general fungicide such as Daconil. It will be difficult to eradicate, but you can slow it down. If you have a tree that gets it every year, a preventative spray may help, but if it was an isolated incident, use good sanitation this fall and see what happens next spring.
May 21, 2016
I bought 3 crepe myrtles a few years ago, red, white, and purple. After a couple years, the red quit blooming. I replaced it after 2 non blooming years. I moved it, instead of destroying it, but want to know if there is any way to get it to bloom again?
Crape myrtles bloom on the new growth. The only thing that would totally keep a crape myrtle from blooming is lack of sunlight. The more sunlight they receive, the more they bloom. Winter damage in 2014 and 2015 did cause some delay in blooming, but eventually they did have flowers, just maybe not as many.
April 23, 2016
We received an email from a local nursery that recommended treating all crepe myrtles with Bonide Annual Tree & Shrub Insect Control in late April or early May due to the prevalence of Crepe Myrtle bark scale in west Little Rock. It also recommended following up in late summer or early fall with Bonide Systemic Insect Control. Would you share your thoughts and recommendations about this topic? We enjoy reading your newspaper column.
I personally think that is an extreme approach. While we are getting more and more cases of the crape myrtle barks scale, it is not something that I would do a preventative program for. While the insect can cause problems with blooming, it is not something that is going to kill a crape myrtle overnight. If you monitor your plants regularly, you can first detect a problem, and then take action if needed.
April 2, 2016
I live in a condominium complex which was built in the 70's. We have many old, large crape myrtles which have been "murdered" year after year and have the resulting ugly knots. How can we get them back to their natural growing form? What do we do about the knots?
You have a few options. One is to cut the knot off and then choose up to three of the sprouts that grow and prune everything else out. You can also keep the knot and again let the sprouts begin growth and choose up to three of the new sprouts to train into trunks. Next year, take the three new branches that you chose last year and only prune them where they get smaller than a pencil in diameter. Eventually they will form into well-structured trees with beautiful bark. It won’t happen overnight, but it can be done.
March 19, 2016
My husband and I live in Texarkana. We went out this morning to cut back our two crepe myrtles which we planted at the corners of the front porch 20+ years ago. We've never had any trouble with the crepes, but this morning we discovered that one of them looks like it has been burnt (pictures attached) and has white patches down the length of the tree with white tiny round things where the bark is peeling. The tree on the north end of the porch is in the most trouble but the other tree is beginning to look the same but is less severe - so far. Could you tell me what is causing this and what can be done; or, should we cut them down and start over?
You have a classic case of the new insect on crape myrtles called crape myrtle felt scale. The black color is coming from a sooty mold that forms on the sticky residue given off by the scale insects feeding on the tree. From the pictures, it also likes you all practice ‘Crape Murder’ in your pruning of your crape myrtles. That huge knob you cut it back to is not the most attractive way to prune a crape myrtle. The scale insects will not kill the tree, but it can reduce the amount of flowers in the summer. I would use a soft brush with soapy water and clean the trunks, then spray with a dormant oil right now. In a few weeks you can use a systemic insecticide around the dripline of the tree to kill the insects. Here is a link to our fact sheet on this new pest problem http://www.uaex.edu/publications/PDF/fsa-7086.pdf which we are seeing from Little Rock south. Each year we get more and more reports of this pest.
March 12, 2016
I feel sure that you have previously discussed this, but it would be helpful to everyone if you would go over the treatment for crepe myrtles that are infected with the disease that is going around our area of the state. This is the one that is most obvious by the large amount of black sooty deposits under the tree or shrub itself and on its leaves. I am a volunteer who works with the Lakewood Improvement District here in North Little Rock. We have eight or ten large crepe myrtles that are infected. Obviously, we would like to treat these plants. We hope that you can advise us.
The relatively new problem you are referring to is not a disease but an insect—the crape myrtle felt scale. The small white felt covered insects attach themselves to the tree and suck sap out of the plant. As they feed, they give off a sweet substance called honeydew. Where the honeydew forms on the trunks, branches and leaves, and black sooty mold forms. Before the trees leaf out you can get in and using a small soft brush wash the trunks with a soapy solution to clean the trunks of the sooty mold. A dormant oil can be used in late fall through mid-winter, but you are getting a bit late for that to have much effect. In a few weeks, apply a systemic insecticide containing Imidacloprid around the trunk of the plant. Mix according to the label instructions. The plant will absorb the insecticide as it is moving energy throughout the plant. This will kill the insects. Once dead, they won’t disappear, but you should see no new signs and there should be no more black sooty mold. We are entering our third growing season with these insects and get more reports of them all the time. So far we seem to have them from Little Rock and points south. While the scale insect will not kill a tree instantly, it can impact the blooming of the tree and the overall health. Don’t treat every crape myrtle in your yard, just those that are impacted by the scale insects. Research is ongoing across the south to determine if there are any varieties that are resistant, and looking at other methods of control. Here is a link to our fact sheet http://www.uaex.edu/publications/PDF/fsa-7086.pdf on this problem and a link to a story I wrote about it last year: http://www.uaex.edu/yard-garden/in-the-garden/crapemyrtlescalebark2015.pdf
March 1, 2016
Last year you wrote about a new insect pest on crape myrtles. I didn’t pay a lot of attention, because I didn’t think I had the problem, but now I think I do. I was pruning my plants and there are some branches that have little white things on them. Is this the pest and if so, what do I do about it? I love my crape myrtles and would not want to lose them—and I don’t murder mine either, thanks to you. How did the insects get to my yard?
Crape myrtle felt scale is the name of the pest, and we are seeing more and more new cases every year. The insects could travel from tree to tree in a nursery or in neighborhoods, or be transferred by pruning one tree and then another without cleaning off the pruners. Putting damaged branches out on the curb and then loaded into an open truck with other yard waste could allow them to escape and attack other trees. So far we don’t consider the pest to be deadly to crape myrtles, but it does affect the size and the amount of flowers, but I think it would take years growing unchecked to kill a tree. We have seen excellent results with the systemic insecticides containing Imidacloprid (Merit, Bayer Advanced Tree and Shrub, etc.—all same chemical just different brand names). Systemic insecticides would be best applied as the trees begin growing this spring. Prune out any heavily infested branches or you can clean them off with a soft brush and warm soapy water, and then use the soil drench with the insecticide.
February 20, 2016
I would like your advice on how and when to plant Crepe Myrtles. I live in Sherwood and want to plant them in my front yard. There is plenty of sun, however I do not know the soil content and so I also need advice on preparing the soil also. Could you please help me?
Crape myrtles are wonderful plants for Arkansas summers. They thrive in heat and full sun. Find a location with plenty of sunlight and a well-drained soil. You can have your soil tested now to see what the pH is and overall nutritional levels. If your soil is rocky, amending with some compost or organic matter is ideal, but don’t just amend in the planting hole—try to amend at least three times as wide as you plan to plant—this will encourage the roots to spread. There are many good choices of crape myrtles, from dwarf almost groundcover forms to standard trees up to 30 feet in height, and all sizes in between. Here is a link to our crape myrtle database which gives you flower color, mature size and form, and bark color. http://uaex.edu/yard-garden/resource-library/crape-myrtle/
I would begin to plant crape myrtles from mid-spring through mid-summer, so you can get them established before cold weather hits in the winter.
February 6, 2016
I have seen a strange sight in Texarkana for about 3 years now. At shopping centers, where landscaping services take care of the plants, they have already starting the crepe murder (ugh!) for this spring, but also seem to be burning the bark. It looks like they take a blowtorch to it. Strangely enough, most come back and bloom, but it looks horrible. Do you know why they do this?
I do not think they are burning the bark. I think the trees are infested with the crape myrtle scale. Heavy infestations leave the trunks covered in a black sooty mold. If left untreated it can severely affect the blooming of the tree. So while they are not burning the trunks, there is still no excuse for the pruning known as crape murder!
February 1, 2016
We have a lot of plants planted in the corner of our yard and the utility company needs to come in and do some new pipes. I will have to move a 10 foot southern magnolia, a crape myrtle trees, along with numerous perennials. When should I transplant these? I am not sure when they will be doing the work, so I may have some lead time to plan.
We are in prime transplanting season for your trees. With the perennials, you may or may not know where they are until they begin emerging. If you plan to replant them back in the corner after the work is done, you can heal them in a shady area in the yard—mounding soil over the root system until you can replant. If you are permanently replanting, dig and replant immediately. While they are dormant, there is less stress to the plants.
October 3, 2015
I have had success with the soil drench in the spring for controlling the crape myrtle bark scale. What about that type of treatment later in the year (summer and fall)? Is it still effective? I am seeing it on some of my other crape myrtle trees now, and I don’t want to wait until spring to take action. Is the dormant oil as effective as the drench? Also, you mentioned in your article to not treat the trees preventively. Is that an environmental issue? What if there are several trees and only one has damage?
The way the drenches work is through movement via the sap. In the fall and winter there is not much movement upwards. They tend to be preparing for winter and storing reserves in the root system, therefore the product is not as effective as it is in the spring when we get strong upward flow. Preventative is in my opinion overkill, since we don't know if all plants will be affected. There is still a lot of debate about the effects of the neonicotinoids and the bees and beneficial insects, so using it as needed versus blanketing the landscape is my preference. We have seen a rash of attacks in the past two months, and we aren't sure if it was due to drier conditions or what. The dormant oil is not as effective, but it gives you the beginning of control, and should keep them in check until you treat in the spring.
September 26, 2015
I live in Nashville AR and wrote a couple of years back, and sent a photo, of an infected tree. You recommend dormant oil, but that tree went on to die. We have 3 young crape myrtles (Natchez I think), planted two years ago that are infected. The nursery sent a worker out to spray the tree and apply an insecticide to the soil. It is too early to tell if the treatment will be therapeutic. From your article, I need to aggressively prune late winter, wash, and use dormant oil. Or should I start over with a different variety? I noted it was first detected in Dallas and spread over the south. Our first tree and these 3 above all came from the same nursery in Texas. Do the trees come into a nursery already infected or do they become contaminated at the nursery? Or where does this pest come from? You mentioned several insecticides applied to the soil. Which, in your opinion, is the best?
all good questions and unfortunately no definitive answers. We have seen that some varieties tend to get it more than others, but we don’t have enough data over a long enough period of time to know for sure. Where I did the photo shoot for the story two trees were totally infested and the dwarf crape myrtle beside them, had no damage. The insects could travel from tree to tree in a nursery situation, or be transferred by pruning one tree and then another without cleaning off the pruners. Putting damaged branches out on the curb and then loaded into an open truck could allow for spread too. I do not think your crape myrtle would have died at least that quickly from crape myrtle scale. I have seen trees literally covered with them and still living. It does affect the size and amount of flowers, but I think it would take years growing unchecked to out and out kill a tree. We have seen excellent results with the systemic insecticides containing Imidacloprid (Merit, Bayer Advanced Tree and Shrub, etc.—all same chemical just different brand names). Only prune out heavily infested small branches, clean the main trunk and then spray with a dormant oil this late fall to early winter. Systemic insecticides would be best applied as the trees begin growth in the spring. I would not give up on planting crape myrtles, just stay on top of things.
I know this question has been asked over and over, but I have to ask it again cause my daughter and I are having a debate about this. When is the best time to prune Crape Myrtles?
I do believe this ranks as the number one question I get on gardening, and yet as many times as I have answered it and written about the correct way to prune a crape myrtle, we consider to see crape murder across the state. Late February is the normal time to prune a crape myrtle –prior to new growth beginning. This past late February we were under attack by snow and ice, so many did not get around to pruning until late March—so timing will be determined by weather. If you have a standard crape myrtle prune it with three to five main trunks or a single trunk. Let the branching begin about 5-6 feet off the ground and prune out anything smaller than a pencil in diameter, any crossing or rubbing branches, and then let them grow and become trees.
I have just found the crape myrtle scale on my crape myrtle tree. I hadn't noticed it when the tree was covered in leaves, but now I see black and white up and down the trunks. What should I be doing now?
If the tree is heavily infested, you can use a soft brush with warm, soapy water and
clean it now. Then you can saturate the trunks with a dormant oil to help kill any
remaining scale. In late winter/early spring apply Bayer Advanced Tree and Shrub
insecticide or a product containing the systemic Imidacloprid.
I need to reread a piece you did a couple of weeks back on a disease, fungus, or blight you did on crape myrtles. I am reasonably certain I have that problem. I need to know how to deal with it please. I live in Nashville, Arkansas and got the tree from a nursery in Texarkana. I noticed the problem last summer. Should I cut the tree to the ground and retrain it?
The problem is not a disease but an insect—a new scale on crape myrtles. First found this fall in west Little Rock we are now getting reports from other areas of the state as well. From the pictures you sent in, you do have the felt scale. Your tree is small enough that the outer bark hasn't started peeling yet, so you should get thorough coverage with dormant oil. I don’t think cutting it back is the answer. Try using the dormant oil and monitor this season. Before you spray, use a soft brush and soapy warm water and clean off the stems. When dry, spray with dormant oil all over the tree and the surrounding ground underneath, since some of the scales will surely have fallen there. Systemic insecticides applied this growing season may also help. Here is a link to our new fact sheet on the problem: http://www.uaex.edu/publications/pdf/fsa-7086.pdf
In front of our house we have two 17'x17' plots of ground between sidewalks. We would like to plant a tree in each plot that would not eventually lift the sidewalks with their roots and would not get too tall. We have tried dogwoods, red buds, flowering cherry, but the full sun and heat got to them. Someone suggested Bradford pear, but my wife and I are allergic. Are there any other trees that we might plant that have a better chance of survival?
Definitely not a Bradford pear—they can get 40 feet tall and 40 feet wide—way too large for this location. You have several options. The new trend in trees is to produce fastigiated forms—those that grow with a narrow growth habit. Fastigiated sweetgum, fastigiated hornbeam, English oak, and Autumn Spire red maple are just some choices that would work. These would get tall, provide shade, but would fit the situation with a narrow canopy. Smaller trees to choose would include redbud (they usually take full sun well), crape myrtle, and fringe tree.
My husband and I are going to trim the crepe myrtles on Military Dr in NLR for the Amboy Neighborhood Association. When is the best time to trim crepe myrtles? Also, can the bushy ones be thinned down to three or four stalks and trimmed up like trees?
The best time to prune crape myrtles is before new growth begins in the spring—typically late February. It is preferable to trim a standard variety as a tree, instead of a bush, but it can take a few years to change.
I live here in Little Rock & have just recently planted 2 crepe myrtles on Sept 22. I watered them the first day after we planted them & put some blood mill in the soil, but neglected to water them after that. It rained Sunday & so the soil is still moist. The problem is that the leaves have mostly fallen off & the ones left are pretty dried up looking. What can I do to salvage them?
I think it is very unusual for the leaves to have dropped this quickly after planting. Since Sept. 22 we have had a bit more rain, and milder temperatures than we did for the bulk of the season. Transplant shock can occur, but I think you have a pretty dramatic display. Newly planted trees and shrubs are much more dependent on water than those that are well established, but I would still contact the business where you purchased them and ask for advice. Your only other recourse is to wait and see what happens next spring. Be aware that crape myrtles are one of the last plants to begin growing, so don’t despair too quickly.
When is the best time to take a cutting from a crape myrtle tree to start a new plant?
Crape myrtles can be rooted from cuttings taken from late May through mid July. The key is to take semi-hardwood cuttings—the new growth that has started to harden off a bit. The cuttings should be around 3-5 inches in length and contain no flowers or seed heads.
I have 3 gorgeous crepe myrtle trees 25-30 feet high and planted in a line 15+ feet apart. They don't look stressed but haven't bloomed this year. They have never been pruned but the canopies have started to grow together. Are they mature and therefore not blooming on new growth? Should I have them trimmed (by an expert of course) or could it be a chemical problem? They are in full sun.
You aren't alone, even the crape myrtles seem to be affected by this hot, dry weather. Many are not blooming, and those that are have much smaller than normal flowers. For those that have finished blooming, deadheading—removing the spent flowers can encourage them to bloom again, but since yours haven’t started yet, try giving them really deep soaking water. While crape myrtles are extremely drought tolerant, and won’t kick the bucket, or even appear wilted, they will slow down and stop performing when it gets really dry. Look around at neighbor’s landscapes—often the greener and more lush the garden, the more flowers you will see. If you can’t or don’t want to water, the crape myrtles can hang on, and if we get a break in the weather, there is still ample time for them to flower.
I need some info concerning a crepe myrtle plant. It came with the house 8 years ago and was then a well established plant that has bloomed beautiful every summer. A couple of days ago I noticed that the blossoms were not as dark pink as in previous years and upon further inspection I noticed that the leaves of the whole plant were sticky. I had never seen this on this plant in previous years and am now worried about what to use to treat it with. I did spray the whole plant with Sevin bug spray but don't know how to proceed.
It looks to me like you have a heavy infestation of aphids. As these sucking insects feed, they give off a very sticky substance called honeydew—that is what is causing the sticky, shiny substance on the leaves. Left long enough, the sticky honeydew will turn black as black sooty mold begins to form. Sevin is not a good insecticide for sucking insects. You can use a contact insecticide such as insecticidal soap or Malathion or Orthene which is a systemic. Even a strong spray of water can dislodge them. Aphids multiply rapidly in ideal conditions and can quickly explode in populations
Is now a good time to move 6 foot tall crape myrtles? We live in Little Rock.
I would hold off until the end of February if you can. That is when you can prune them and move them all at the same time. If you absolutely have to move them now, that is ok, but they would be less winter hardy without an intact root system. Make sure they are well mulched and watered if it is dry.
I have several Crape Myrtles from three to six feet tall. They all froze last winter. I cut them down to the ground, as instructed by our local nursery owner, and they came back beautifully in the spring and produced beautiful flowers that lasted a long time in the late summer, with several different periods of bloom. When is the best time of year to cut them back again and at what height to achieve the same production and growth as last year?
If you have standard crape myrtles then try pruning them into a tree again. Choose three to five of the straightest and strongest sprouts and prune everything else out in late February to mid March. Then take off anything smaller than a pencil in diameter. Eventually they will grow back into trees, provided they don't get frozen again.
I need to know what to do about off-shoots from crape myrtles that will not kill the mother tree. I have a tree that is probably 30-40 years old and from its wandering root system, shoots appear every year and this year some are blooming. For years I have just cut them off, but wonder if there is a product that I can use to control them without harm to the main tree.
Continue doing what you are doing. There is nothing you could spray with that would kill the sprouts but not hurt the mother plant. Most of these suckers are attached to the mother plant. Some varieties are more prone to suckering than others, so just cut each season.
Crape myrtle story.
Few plants are as connected with the south as crape myrtles. These plants thrive in heat and humidity and have the potential to bloom all summer long with relatively little care. Lagerstroemia indica or as most know it, the common crape myrtle, was introduced from China and Korea in 1747. Widespread cultivation of the plants started in Charleston, South Carolina in 1786. Today, through hybridization and plant breeding the family of crape myrtles includes a diverse mix of plants, from ground cover forms which are no taller than 8-10 inches up to standard varieties which can grow thirty feet tall or more. Flower colors range from red, pink, purple or white. They are a staple in Arkansas landscapes. The common crape myrtle was already entrenched in southern landscapes when the Japanese crape myrtle, Lagerstroemia faurei, was brought to the United States in the 1950’s. This cold-hardy crape myrtle had beautiful red bark and was resistant to powdery mildew—a common disease of the crape myrtle. The only downside to the new introduction, was it only came in one color—white. Dr. Don Egolf was a plant breeder extraordinaire at the National Arboretum in Washington, D. C. and he began an extensive breeding program on crape myrtles, crossing the L. faurei with L. indica. The goal of the breeding program was to combine the beautiful bark color, cold hardiness, and disease resistance of the Japanese crape myrtle with the variety of flower colors of the common crape myrtle. Egolf made thousands of crosses between the two species and came up with many new forms of crape myrtles. Thanks to these efforts, the National Arboretum has released over 29 varieties into the nursery trade. The University of Arkansas also has released several varieties of crape myrtles including ‘Centennial’, ‘Hope’, and ‘Victor’. The most popular variety from Egolf’s trials was ‘Natchez’. This standard crape myrtle can grow 30 feet tall or more and has outstanding cinnamon colored bark with white flowers. The first true miniature was discovered in 1989 called ‘Chickasaw’. This pink flowering plant grows no taller than 20 inches and spreads 26 inches wide. Today, new varieties and forms of crape myrtles hit the market annually. Trying to keep up with what is available can be difficult. The National Arboretum has compiled a chart as a quick guide to differences between their 29 released crape myrtles: including descriptions of flower color, bark color, fall color, plant size, and growth habit. You can view it at: http://www.usna.usda.gov/PhotoGallery/CrapemyrtleGallery/CrapeTable.html. You can also click on http://www.usna.usda.gov/graphics/usna/Newintro/USNA_CrapeMyrtlePoster.pdf to see a poster of the National Arboretum crape myrtle introductions. Our University of Arkansas Extension web site also has a good reference guide to varieties of all sizes, shapes and colors that can help you choose the right plant for your landscape. You can see it at: http://www.aragriculture.org/horticulture/ornamentals/crapemyrtle/pdf/detail_all.pdf While crape myrtles are easy plants to grow, they do have their problems. Number one is the gardener in charge of pruning them. “Crape murder” is a common refrain and visible signs of this dot our landscapes—usually more commonly seen when the plants are devoid of leaves. Repeatedly cutting standard, large growing forms back to large knobby growths in the winter is a common practice gardeners use to keep the plants the size they want them. If the plant is getting too tall each year, and you have to prune them to keep them out of the eaves of your house, then you planted the wrong variety. With proper selection, you can choose plants that at maturity fit the size you need. Trying to tame a tree into a shrub is a constant battle. When choosing plants you really should read the tag and determine.
We would like to plant two dwarf crape-myrtles in our back yard and would like to know if any have the pretty red bark for winter time.
Unfortunately, the dwarf crape myrtles do not develop pretty bark like the standard varieties.
I have a crape myrtle tree that has many shoots or suckers growing around the trunk. Can I dig one up and replant it and expect it to grow? Do I need to do anything to it?
Many of the suckers on your crape myrtles will be devoid of roots as they are attached to the mother plant. You can root these shoots, but you could not take them off the plants now and leave them outdoors. They would not survive the winter. You could try rooting them inside in a container with potting soil. Crape myrtles root rather easily from cuttings taken June – August. I find it easiest when rooting cuttings without a greenhouse, to take multiple cuttings—4- 6 inches in length and dip them in a rooting hormone, then put them in sterile moist potting soil. Put pot plus cuttings inside a clear plastic bag, seal that up and put it in a bright location, without direct sunlight. This will create a miniature greenhouse, with constant moisture and humidity and should aid in germination. The woodier the cutting the longer it will take to root.
After several years of trimming my crape myrtles back, there is a large knot where the new growth comes out each year. Should I continue to trim as in the past or should I cut the tree below the knot or does it really make any difference? They are mature and the knots are about 5 feet high.
If you have those gnarly knots or knees, then you are not trimming your crape myrtles, you are butchering them. Cutting them back to those ugly knots or every year encourages loads of new sprouts which grow rapidly then fall over under the weight of the flowers. The key if you have standard crape myrtles is to allow them to grow into graceful trees. You have two options since you have the knots. You can either cut them out or gradually let them outgrow it, cutting off everything less than a pencil in diameter and thinning out the number of branches emerging from the knots to no more than three branches. For those starting with young crape myrtles, the best way to achieve a beautiful tree is to leave three to five main trunks, making sure that there is ample room between each trunk to achieve mature size and width. Let the trunks grow to a height of five to six feet before pruning and then start shaping them into a tree. Depending on the variety, your crape myrtle can be a ground cover Lagerstroemia ‘Razzle Dazzle’, a dwarf getting no more than 3-4 feet or a standard growing 20-30 feet tall. Know what you want before you buy them, and then allow them to grow into what they were supposed to be. An excellent database on crape myrtles—heights, colors, etc is on our extension website at: http://www.aragriculture.org/horticulture/ornamentals/crapemyrtle/pdf/detail_all.pdf
Is it too late to prune crape myrtles? My neighbor pruned hers in November, and I just have not had time to get it done. The trees are ten feet or more in height, and I see them 3-4 feet all over town. Help!
You have probably all heard of the “rape of the crapes” or “crape murder”, and that is what I think is occurring whenever the plants are sheared back to three or four feet. If you are growing a standard crape myrtle, it has the potential to be a small tree, growing up to 20 feet or more. Let it grow up! They have outstanding peeling bark, and interesting branching patterns. If you don’t have room for it to reach its mature size, consider moving it to a location where it does. Blooming may not be as large per stem with taller plants, but you will have more blossoms and they won’t cause the branches to droop over, and you get the benefit of mature bark. To answer your question, it is not too late to prune crape myrtles, but please don’t butcher them. You do want to prune to make sure you have good branching structure, and that you keep a fairly open plant, but yearly shearing is not good!
I have heard your response on how to properly prune a crape myrtle, but I have one unanswered question. We purchased a house with several crape myrtles that have already been cut back to that loathsome four foot height. All small branches have been removed and each crape myrtle has about five main trunks. If I want to let them grow as you recommend, should I cut all the branches back to ground level in one fell swoop or will that kill the plant? I don't want the pollarded look at the four foot height, and I don't want to aggressively prune the crape myrtle every year. I suspect the plants are ten to fifteen years old.
It is February, so it is the proper month to prune a crape myrtle. Unfortunately, if you have a tree that has been butchered in the past, it is not a quick fix. You do have some options. One would be to do as you ask, and start over by cutting the plant to the ground. This will take time to restructure the tree. If you do this, choose three to five sprouts that appear, and prune out everything else. Gradually shape it into a tree. The other option is to cut out the knobs and then choose one sprout that appears from that point this growing season and grow it into a tree, or prune to the strongest branch that is growing above the knob and let it become a true branch, cutting out all the other twigs from that knob.
I found some silvery stuff on the end of the leaves of my crepe myrtle. The others are blooming right now, but this plant is not. What should I do? Prune off the bad leaves and branches or spray it with something or use some kind of systemic stuff?
It sounds like you have powdery mildew on your crape myrtle, a common fungal disease. Some varieties are more susceptible to it than others. If you have a heavy infestation on the tips, try pruning it back, but not by much or you may delay blooming even longer. Use a broad spectrum fungicide such as Daconil, Funginex or Immunox. Spray once, wait two weeks and spray again. Then see what happens. It is often difficult to get a handle on the disease once it kicks in for the season. Make sure when pruning your crape myrtle next year that you try to keep the center as open as possible to allow for better air circulation and sunlight input.
We set out crape myrtle trees this summer. When is the best time to trim the lower branches so that it will bush out more at the top? They have done very well.
Pruning lower limbs is not going to have much impact on branching at the top of the plants. Removing lower limbs gives you more of a tree like appearance, but to encourage better branching at the top, prune to buds on upper branches to encourage fullness. Pruning of crape myrtles should be done in late February to early March.
I have what I think are several dwarf crepe myrtles in the flower beds around my home. They grow in a bushy mounded shape and I would like to prune them back some. (They are bare right now.) When is the best time to prune them? What is the correct way to prune them? I know how to prune my large tree-like crepe myrtles, but I have never pruned the dwarf variety.
Dwarf crape myrtles never produce beautiful bark like their tree-like counterparts, so correct pruning is not as much of an issue here. I still prefer to wait until late February to prune them for added winter protection, but you can prune them back by half or more every year. The key here is to encourage new growth, keep them in the height range you want and let them bloom on the new growth. With some of the newer varieties of dwarf crape myrtles they are grown as ground covers and spread wider than they do tall.
We have a crepe myrtle that has not been trimmed for 20 years. It has branched out at least 20 feet wide with many stems (or trunks) some of which are four inches in diameter and the base is probably 30 inches in diameter. It must stand 12-15 feet tall. How do we trim it back? When do we cut back? Where do we start? Another crepe myrtle nearby is much smaller but is beginning to spread the same way. How should it be trimmed?
Crape myrtles come in a variety of mature sizes from ground covers to mature trees getting 25-35 feet tall. My preference is if you have the standard tree forms that you allow them to be trees. I like three to five main trunks and everything else pruned out. Then shape them with a good branching structure. Twenty feet wide is more a large bush. Thinning them out and reshaping may take time, but at least they aren't cut back to those ugly knobs every year. The best time to prune is late February to mid March after the bulk of winter weather has passed.
We recently moved into a house with six well established crape myrtles in the front yard. The problem is that they have been whacked on pretty bad and have huge ugly knots. They have flowered well but still have knots that just look disgusting during the winter months. Should I get out the big saw and cut these trees back below the knots or are they supposed to be cut above the knots or what? I've watched your pruning video but nothing is mentioned about trees that a person "inherits" which have been butchered. I'm a newbie with these beautiful trees and would like to clean up the mess that has been made and give them a chance to start over. Can you possibly give me some very detailed instructions for how to make them look good again?
You have a couple of options. One is to cut off the horrid knots, and then when multiple sprouts begin growing this spring, choose two to three of the sprouts and prune all the others off. Then next spring, prune off anything smaller than a pencil in diameter and gradually grow some taller stronger branches. The other option is to leave the knots but choose three of the strongest branches that are growing from them, and prune off everything else. Eventually you can restructure them into beautiful trees which are as pretty in the winter as in the summer and fall, but it will take several years.
We would like to plant two dwarf crape-myrtles in our back yard and would like to know if any have the pretty red bark for winter time.
Unfortunately, the dwarf crape myrtles do not develop pretty bark like the standard varieties.
We have a crepe myrtle that has sprouts which requires constant trimming of about 6 inches thick around the base of the tree. We are tired of trimming. What can we do to kill the sprouts without damaging the tree? The tree is in an open grass yard on the north side of our house - not a flower bed.
Just keep trimming. Any chemical that would kill the sprout would damage your tree. Some trees are just more susceptible to sprouts than others. But do keep them removed or you will end up with an overgrown bush.
I have a few young crepe myrtles planted along the south side of the house. They are about 2 years old, now. I believe they contracted "powdery mildew". I checked the extension website and used a systemic treatment on them per the website. The powdery mildew seemed to slow down, but it did not go away. What should I do now? Will it come back next spring? My sister said she thought I should cut off all the mildewy looking limbs and leaves now.
This late in the year, I wouldn't do any more spraying or pruning. The key is good sanitation. As the leaves fall, rake and destroy them, but you don’t need to prune out the branches. Some varieties of crape myrtles get powdery mildew every year, and others rarely have it. If you have a variety that is highly susceptible, consider a preventative fungicide application next spring, before you see the disease. Also, prune the plant to make sure that the branches are spreading out with good air circulation and sunlight penetration. Folks who severely cut their crape myrtles back every year end up with an excessive amount of foliage which cuts back on air circulation and can make the disease worse.
Three years ago I moved 4 large Natchez crape myrtles that were planted too close to the house. We used large equipment, paid attention to the root system and the move was successful for all 4 trees. Last year they all developed a significant aphid problem and we finally controlled them with spraying an insecticide. The trees lost a significant number of leaves to the aphids and developed a black fungus. This spring we repeated the insecticide application and we were aphid free until about 2 weeks ago when they reappeared. Malathion spray took care of them for the moment. The trees get frequent watering and bloomed beautifully this year. Any ideas on why this occurring and how stressful is this on the trees?
Aphids tend to build up when it is hot and dry and often attack healthy plants quicker than those that are not as healthy. We had the ideal conditions for them late in the season. I would not be too concerned with aphids this late in the year. A strong spray of water can knock them down, but the leaves will soon be falling anyway. If you have a plant that tends to get insect attacks annually, you could use Bayer Advanced Tree and Shrub insecticide in the spring when the leaves begin to emerge. It should give you a season of control. Don't treat all plants in your yard--just those that seem to be attacked each season. Luckily for us, aphids are easy to kill once they occur, but they do multiply at an alarming rate. They attack a wide range of plants, and if allowed to continue feeding unchecked, they can do some damage. The black you mentioned is black sooty mold which grows on the sticky honeydew the aphids give off after feeding. Control the aphids, and you will control the black sooty mold
I need some help and information regarding our crape myrtle. Before we moved into our new home in September the builder planted a crape myrtle tree and it was blooming beautifully. The crape myrtle started to leaf out this spring and then we got hit with another hard freeze; the trees new growth was killed off. It finally started growing again in the spring from the bottom up, but it had a lot of dead branches on top. My husband cut the dead branches off, but since then the tree has not bloomed. Did he prune the tree incorrectly to discourage the blooms? We live in Bentonville.
You aren't alone in the damage to crape myrtles. They were damaged somewhat statewide, but annihilated in Northwest Arkansas. They were well ahead of their normal schedule due to the mild March, so the late freezes did even more damage. For now, you simply must be patient and gradually retrain them into trees. Many crape myrtles bloomed more sparsely than normal if at all this summer. What I like to see in a crape myrtle are three to five main trunks and branching beginning about five to six feet off the ground. Prune as needed next February.
I read all your wonderful info I could find on crepe myrtles, however, I didn't see this answer. It is now March and I have arrived home to find my crepe myrtles leafing out. I wanted to prune them back, but do I dare do it now with new growth on them? I need to as they are taking over our home.
While it is true that we like to get the crape myrtles pruned prior to new growth beginning, this year things got moving a little quicker than normal. You can still prune without impacting the first blooms by much, but do it soon. The later you prune a summer blooming plant like crape myrtle, the later your first set of blooms may be since they bloom on their new growth. Make sure you know why you are pruning and don't butcher them into ugly knobs. I have seen the worse forms of crape "murder" this year than ever. Let these wonderful trees produce large trunks and let them become trees if you have room for them to grow.
My eight foot tall crepe myrtles leaves are covered with black soot. What is causing this and should I do anything this late in the season to help it?
You must have a good crop of aphids. Aphids can attack crape myrtles, especially in dry seasons. Aphids suck sap and give off a sticky substance known as honeydew. When the honeydew coats the leaves a black sooty mold will follow. The only control is to control the aphids. This late in the season, I wouldn't be overly concerned. Take a garden hose and spray down the trees and see if you can knock down your aphid population. Rake and dispose of the leaves when they fall.
We moved here from Colorado and had a landscaper do some work in our yard last summer. I like the Crepe Myrtles and wanted some in my flower bed next to house. He said they would do fine there since they can be pruned back to whatever shape desired. Since then I have had neighbors say they do much better away from house so they can grow larger. The ones put in are not the small-type-bushes, they are the larger bushes. Should I move them away from house and give them more space in yard? Does it damage Crepe Myrtles to prune them back each year keeping them at a smaller size? Also, would it damage them to move them as they were planted July, 2005? Just not sure if these Crepe Myrtles will get too big in 3 to 5 years. There are 7 of them next to house. Any help you can give me will be much appreciated. I also learned to check out landscapers a lot better in future.
It is quite obvious from the butchered crape myrtles all over the south that crape myrtles can be severely pruned each year with no loss of life, but I am with your neighbors in that they will be more attractive plants if they are given space to grow and allowed to do so. Standard crape myrtles have outstanding bark if they are allowed to become trees and their floral display is nothing to sneeze at. There are dwarf varieties that can and often should take severe pruning each year, and they might be good replacements. Crape myrtles can be moved, and yours are still young. I would have preferred to move them in February, but it can still be done now, if you are prepared to water and allow them to wilt and look sad for a week or two. Crape myrtles aren't the only "trees" that some landscapers plant as foundation plantings. I cringe when I see river birch and Bradford pears planted next to a house--they are large trees at maturity!
We have several crepe myrtles on the south side of our house. For the past two years, they bloom early and then they never bloom again. They have buds but they don't bloom after the first blooming. There are lots of buds and the limbs get heavy and lean to the ground. They get approximately eight to ten hours of sunlight in full summer. They have been planted for six or seven years and at first, they bloomed all summer. The last two years, they appear to bloom once. Can you give me any idea what is wrong or what we can do to get maximum blooms? I use fertilizer three times a year on my landscaping so they should get plenty of fertilizer.
This year after the first series of flowers, deadhead the old blooms--cut them off. This will prevent them from setting seed, which is what I am suspecting you are seeing after the first blooms instead of buds that won't open. If you can deadhead each time the plant finishes flowering, it will direct more energy into blooms and less into seed set. Let me know if this doesn't work. Crape myrtles are not heavy feeders, so one application of fertilizer per year should suffice.
I love your column and read it on a fairly regular basis but don’t believe I've ever seen a question in regard to a black mildew looking substance that is all over our crepe myrtles. We have a yard service but they don't seem to be of much help. Do you have any idea what I might be talking about or would you need to look at some leaf samples? It's all over the trunk and limbs as well and has even spread to some of our landscape lighting.
The problem you are experiencing is called black sooty mold. It is a by-product of insect damage. Either the crape myrtle or a nearby large tree had a problem with aphids this season. As the aphids suck sap out of the plant they excrete a sticky substance called honeydew. It was quite prevalent this fall--if you ever parked under a tree your windshield was covered in it. Whatever the honeydew accumulates on eventually gets the black sooty mold if it is not washed off. You can even get a black covering on patio furniture, or other non -plant materials such as your patio lights. The only way to prevent sooty mold is to prevent aphids from building up. Many insecticides, even a strong spray of water can control them, but they are quick breeders and are often worse in hot, dry periods. For now, you can simply wash the black sooty mold off the lights, and hose off the trunk of the crape myrtle.
My crepe myrtles need your help! Every year I fight powdery mildew on my crepe myrtles. Beginning early in the spring, I spray Immunox on a 10 day cycle. This year, in spite of rigorous effort, I have failed. My next door neighbor has a large un-kept crepe myrtle that spreads powdery mildew throughout the neighborhood so I dare not stop the Immunox. This summer another pest attacked my seven trees. Aphids and white flies infested the trees. At first notice, I contacted a local nursery and was told to spray Malathion on a one week cycle. I did. However, the aphids and flies thrived on the chemical and within two weeks, every leaf on every tree was covered top and bottom with aphids and flies. The leaves even became sticky with some sort of bi-product of the aphids. I returned to the nursery and was told to increase the Malathion cycle to every three days while continuing the Immunox on its regular 10 day cycle. I did. The results were the same, more mildew, more aphids, more flies. If that wasn't enough, the crepe myrtles then contracted some sort of black mildew which covered not only the leaves but also the bark on smaller limbs. So here we are approaching the end of the season. Some of my crepe myrtles have not bloomed even though they are well established trees instead, they are defoliating. My biggest concerns now are to ensure their survival and learn what must be done through the winter and into next spring to return the trees to health so we can enjoy full bloom next year.
Wow! I am not sure seven plants are worth so much effort! You are definitely giving it the college try. Powdery mildew can be a difficult disease to control, but usually it is more of a problem if you allow it to get established, versus preventative spraying. Immunox is a good product. You may want to alternate with another fungicide to prevent the plants from building up a resistance next year. Pruning the plant to make it more open and airy can give you better air circulation and sunlight penetration. As to your insect issues: aphids are usually not difficult to kill but can multiply rapidly if you give them a chance. Whiteflies can be more of an issue. Both insects feed by sucking sap out of the plant and then they give off a sticky residue called honeydew. If the honeydew is present, you then get black sooty mold, which only grows on honeydew. Since this was your first attack of insects, you may want to wait and see if they reoccur--not do prevention next year. If it becomes an annual problem, there are several options. One is the Bayer Advanced Tree and Shrub insecticide. You would apply it to the soil in March. It is systemic and can give you a season of control. With white flies, a second application is sometimes necessary in July. Di-syston is another systemic product which can work. While Malathion is a good product, the problem is that it is a contact kill product, meaning you have to come into contact with each insect for it to work. If you have large plants that have dense foliage, you probably are not getting thorough coverage. Those you miss, keep on going. Systemics work by entering into the plant itself. Orthene is a good one to use during the growing season if a problem arises. A combination of fungicide and insecticide is Orthenex, with Orthene and Funginex. As for this year, I would take a garden hose and hose down the tree thoroughly, trying to knock down the aphids and hopefully some of the honeydew. I personally wouldn't spray any more with pesticides this late in the year, especially as hot and dry as it is. Keep the tree watered and rake up any leaves after they fall. Try a different approach to pruning next February trying to keep the plant more open, and hopefully you will have a better season next year.
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