Q. Dear Neil: I moved into a new house last summer. There were two mature crape myrtles, and I’ve followed your instructions on fertilizer and insecticides. With the abundant rain last spring they bloomed beautifully. Now the trees are covered with seeds. I fear the weight of them could break the branches. Should I trim them off? Should I do something different next year?
A. Congratulations on your success. I’m hesitant to recommend that you prune anything off the ends of the branches. People start to do that with good intentions, but they get bored and soon end up topping their trees. When a crape myrtle is butchered by cutting branches back to stubs the size or broomsticks or larger it forces extremely vigorous shoots to emerge and huge flower heads to be produced. That results in large masses of seed heads. In reality, it’s far better for the tree just to let it grow naturally by not pruning anything off the ends of the branches. The fruit will open up and the seeds will fall to the ground. (Very few will germinate.) If an ice storm is forecast you can do a light trim ahead of time to remove some of the surface area, but trim off only the heads and none of the stem growth of the plant itself. I would make no change in the care you gave it this year next time around.
Q. Dear Neil: A tree in my yard has been dripping this black sap all the way to the ground. Is it going to kill the tree? Is there a way to treat the tree, or is it doomed?
A. It looks like you have a cedar elm, and it looks like there is a burl developing in the crotch of the two branches. Burls are abnormal growths that form, often for unknown reasons, on plant tissues. They have greatly distorted grain patterns. It appears that the sap flow originates at that point, so there may be active decay behind the burl. You need to have a certified arborist look at your tree on site to determine the best steps to take.
Q. Dear Neil: What has caused these dead patches in my otherwise healthy Asian jasmine and holly? They turn an odd bronze-metallic color, but the leaves don’t fall off.
A. For starters, I’ve never seen an insect or disease on Asian jasmine, nor have I ever seen either do that kind of damage to hollies. And, even if there were, they wouldn’t attack both unrelated plants simultaneously. So we rule out insects and diseases. This is an environmental issue. These plants have been hit by something that burned their leaves. Things that come to my mind include a large male dog, a hot mower muffler, hot water as a garden hose just starts up, a careless turn while applying fertilizer or herbicide, etc. I wouldn’t be surprised if the twigs don’t put out new growth before this growing season is completely over.
Q. Dear Neil: Starting in late June we’ve been seeing light patches in our lawn. They’ve gotten worse. Nitrogen did not help. I’m wondering about a fungus. What would you suggest?
A. This has been a really bad year for bermuda turf in many parts of Texas. There have been diseases involved, a couple of them being ones that I don’t see very often. For them I’m going to suggest that you send a sample to the Texas Plant Clinic at Texas A&M for culturing and analysis right away. You need precise help on that one. That all said, I see something troubling in the lower right corner of your photo. The browning grass looks like damage of white grub worms. I’m seeing more of that this year than I’ve seen in many years. Pull on the dead areas and if the grass comes loose easily, dig several holes 1 foot on a side and 3 inches deep. If you find 4 or 5 white grub worms per square foot, they’re your culprits. You should apply one of the insecticides labeled for white grubs if you find them. Follow it with a thorough soaking.
Q. Dear Neil: My large pecan tree’s pecans never reach maturity. They develop black spots and fall prematurely. They also have holes in them. What can I do?
A. You need to follow the Texas A&M pecan spray schedule, probably the one developed for home gardeners. It will call for several sprayings during the course of the year. Pecan scab is causing the pecans to turn black and fall prematurely. The holes are either from pecan weevils or hickory shuckworms.
Q. Dear Neil: Why would my sago palm have this extreme leaf curl? I’ve shown this photo to many others and no one has known why it is doing this.
A. In case you want to do any research on it, sago palms are actually Cycads and not true palms. This kind of extreme leaf curl is usually due to stress of one sort of another. The plant may have been kept too moist or its crown may have been submerged too deeply. It’s soil may have been too compacted. Something is just a big off its desired set of conditions. I’ve not encountered this personally. When I search online I see a variety of possible causes, even including a shortage of magnesium in the growing medium.
Q. Dear Neil: We planted these Italian cypresses about 10 years ago. They are about 20 feet tall. In the past couple of years they started turning brown at their bases. Someone suggested they might be getting too much water so I cut back, but they still look bad. Do you have any suggestions?
A. Most of your photos, unfortunately, were taken looking into the light so all I could see were shadows. The one that has detail looks like the lower needles may have dropped due to excessive shading, probably from the other plants nearby. Spider mites are another possibility. You would need to thump small twigs over a sheet of white paper to test for them. If small specks start to move about freely on the paper, those are the mites. You could find an insecticide labeled for spider mite control and spray them. Unfortunately, I don’t think you’ll be able to coax any conifer to produce new needles that far down on a plant.
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