Dear Neil: I have an 18-year-old Texas ash tree. This past year it has lost a lot of its leaves, and now the canopy is very thin. Is there a fertilizer I can apply to get it to fill out better? I really hope I won’t lose it.
A: Texas ash trees are very pretty, but they have several serious issues. Most serious among them would be the borers that invade their trunks. Your tree is probably at its average life expectancy. My bet would be that the trunk has borer tunnels in it already. And now we are hearing of the invasion of another borer — the emerald ash borer that has devastated ash forests in the Midwest. Unfortunately, we have no product to prevent or eliminate this insect.
Dear Neil: I planted five agapanthus plants in May. I watered them every other day. By July they started to decline, and now they look like they’re dead. Will they come back?
A: Agapanthus, also known as lily of the Nile, really does not care for our hot Texas summers. If you think about how few you see thriving in Texas landscapes, you might feel less guilty about having lost the ones you have. It’s time to move on.
Dear Neil: This viburnum beside our front door gets full sun until about 1 p.m. every day. Our local nurseryman says he thinks it has gotten too dry. I have been watering it more, and that has seemed to help, but I’m still wondering if it’s time to replace it?
A: It looks like it probably is. All the types of viburnums I’ve grown in Texas, including sweet viburnums, have done much better without any direct sunlight after mid-morning. I’d suggest an Oakland holly. It would be more upright and more easily kept out of the walkway.
Dear Neil: We have about 200 feet of boundary between our property and the neighbors. We need privacy, and I have seen your recommendation for Nellie R. Stevens hollies. I’ve also seen a recommendation for oleanders. How would you compare them?
A: They are both excellent privacy shrubs. Both will grow to be 12 to 15 feet tall, and both should be spaced 7 to 8 feet apart. The hollies will tolerate shade or sun, but the oleanders must have full sun. Oleanders suffer freeze damage in colder parts of Texas, and they are poisonous to humans. To be fair, however, holly berries are poisonous also. On my own personal rating scale, the hollies would rank far above oleanders.
Dear Neil: What would cause a planting of verbenas to turn brown and crisp very quickly?
A: Spider mites will do that. The leaves begin with fine tan mottling, and within a week look just as you described them. If you thump a piece of the stem over white paper you will see the mites crawling around. You have to spray at first signs of their infestation. Use a general-purpose insecticide that is labeled for spider mites.
Dear Neil: I bought and planted two maple trees 14 months ago. I put weed-blocking fabric over the tops of the soil, and I have rings of stones on the outsides of the holes. I have watered according to the nursery’s instructions, but the trees’ leaves started turning brown back in May. Now they look really bad. I dug down to make sure I wasn’t watering too much. Is it too late to save them?
A: Browning leaves don’t really give specific direction to an answer. They merely indicate moisture stress. It could be from roots lost last fall during the dry weather. It could be because of bark damage due to sunscald. It could be leftover transplant shock. Continue watering and see how they look come spring 2021. That would be the time to replace them if necessary.
Dear Neil: I have a red yucca that was planted eight years ago. It is in full sun, but it has not bloomed for the past two years. I have never dug and divided it. Could that be the problem?
A: I don’t think that has anything to do with it. I’ve seen red yuccas blooming that have been in the same locations for 25 years. Unfortunately, I don’t have a good answer to offer as a counter. I would apply a high-quality lawn fertilizer now and water it thoroughly afterwards, but I don’t know of anything else to recommend.
Dear Neil: My fig plant is losing leaves rapidly. Actually, it was my mother’s plant. She died in 1978. I wonder if I might have let it get too dry this summer? It is on the east side of our house, and I pile tree leaves around it in the winter. The limbs still appear to be pliable.
A: It really has gone into shock, so I guess it is possible that it got too dry. It’s also possible that nematodes might be attacking its roots. Dig up a small part of its root system on one side. Look for swollen galls on the roots. If you find them, that would be evidence of root knot nematodes. There won’t be much you can do about them, but at least you would know what the problem is. You might be able to take cuttings from the plant and get new plants started for elsewhere in your yard.
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 firstname.lastname@example.org.
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