Dear Neil: I’ve attached a photo of my pittosporum. It’s dying in sections. Can you tell what is causing it?
A: Pittosporums put out their new growth in whorls of several twigs at a time. If you track the dead areas back to their origins you may find that there is some kind of damage at the base of each dead portion. However, I really think it’s more likely that the plant got marginally too dry at some point a few weeks before the photo was taken. The dead leaves look like they’ve been brown for several weeks, even a month or two, and the rest of the leaves look rather dry as well. There aren’t a lot of insect and disease problems that bother pittosporums, so I think that’s where I’m going to leave it. I’d suggest trimming out the dead areas and making sure the plant is regularly watered deeply for a few months. See how it comes out in the spring.
Dear Neil: I have squirrels wrecking my Stuart pecan crop again this year. I had a bumper crop, but they’ve invaded from several neighbors’ yards. I don’t think I’ll get any pecans at all. All I’m going to get is a mess on my driveway. What can I do?
A: If there are other trees touching the branches of your trees the squirrels are going to find their way into your pecan. The same goes with power lines and adjacent roofs. However, if the tree is out in the open you could rig up a piece of sheet metal and tie it temporarily around the trunk. If it were several feet high it would make a satisfactory collar to prevent the squirrels from climbing. Have a sheet metal shop crimp it so you don’t cut your hands. You’d need to remove it and put it back into storage after harvest, however, so the trunk wouldn’t be damaged.
Dear Neil: Looking ahead to next spring, our nectarine tree had lots of fruit, but they ended up with spots of what looked like wax. Then the fruit rotted and fell off. What can we do to prevent that next year?
A: Nectarines are basically just “fuzz-less” peaches. The fuzz serves to protect the fruit from insects and diseases. The waxy globs are congealed sap that indicated plum curculio (worms) were in the fruit. Follow the Texas A&M homeowner fruit spray schedules available online.
Dear Neil: What are these obnoxious bushes? I keep cutting them down for my parents, but every time I come to visit, they have regrown. What can I do to be rid of them?
A: You don’t have bushes. You have trees. Vigorous, even invasive native Texas trees known as hackberries. If they have trunks big enough at ground level, cut them off almost flush with the soil, then drill holes into the stumps and pour broadleafed weedkiller in at full strength to fill the holes. Let it soak into the wood of the stump and fill the holes again. You might have better luck in the spring when they are growing more actively.
Dear Neil: When should Knockout roses be pruned and how?
A: All bush roses should be pruned by 50 percent in early to mid-February. With other types you’ll want to make each cut just above a bud that faces out from the center of the plant, but with Knockouts there are so many stems you’ll probably just use power hedge trimmers to cut them back. Finish the job up with lopping shears to remove any dead or damaged internal shoots.
Dear Neil: I have a hazelnut tree that is six years old. It has never had a hazelnut on it, and now it is showing this damage. What is causing it, and what can I do to stop it?
A: This is the work of the twig girdler. The female lays her eggs in the portion of the twig that breaks off and the larvae feed on that wood as they develop. Unfortunately, they do not feed on the tree while they are laying eggs, so there is no way to control them while they are flying around the tree. There is also no way to reach the larvae once they hatch. So sprays aren’t going to work. Your best bet is to gather up all the fallen twigs and put them in a plastic trash bag, then send them off to the landfill.
Dear Neil: When and how should I trim peach trees?
A: Prune peach and plum trees in late January. Your goal is to establish a bowl-shaped tree with three main scaffold branches originating 22 to 24 inches from the ground. Each winter you’ll remove all strongly vertical shoots. Ultimately the trees should be 10 feet tall and 16 or 17 feet wide.
Dear Neil: My oak leaves have what I think you have called galls in the past. Should I try to collect the leaves and discard them this fall, or can I leave them on the ground? What can I do to prevent them next spring?
A: Galls are the result of insects stinging the leaves and twigs and depositing their eggs. There is nothing you can do to prevent them. That’s because they don’t actually feed on the leaves and they’re only there for a few moments. They do no particular harm. Just move on with life.
If you’d like Neil Sperry’s help with a plant question, drop him a note in care of The Eagle, P.O. Box 3000, Bryan, Texas 77805. Or email him at email@example.com.