Dear Neil: In doing some trimming last week, I removed a branch from low on the trunk of a tree. I found a hollow core filled with “goop.” It seemed to follow the limb up a good ways. I’m concerned another tree may be similarly affected. What should I do? I’m worried about structural damage.
A: There has been some type of decay that got started internally and spread through the trunk. As water got in and was trapped, it helped accelerate the breakdown of wood. But don’t do what so many attempt: don’t fill it with concrete. In fact, if the tree has enough value, have a certified arborist look at it on site to determine the best steps to take.
Dear Neil: I planted a Double Knock Out rose bush from a container several months ago. Its leaves look fine, but not its buds and blooms. They don’t open. They just shrivel and turn brown. What can I do?
A: Wait for cooler weather. Roses in Texas have two good blooming seasons: spring and fall. I looked closely, and I don’t see any signs of rose rosette virus, so I think you’re just dealing with roses as normal. Trim them lightly to remove weak, non-budding canes, and apply rose food now to stimulate a round of fall flowers.
Dear Neil: I believe this tree is a maple. My husband planted it 12 years ago. This year it has developed spots on its leaves, and they are dropping every day. What can I do to stop that?
A: Your little maple has very extreme iron deficiency, almost assuredly due to being grown in extremely alkaline soil. I would imagine it did fairly well for its first few years, but then you probably started to see outer leaves that were at first lighter green, then yellow, now almost white. Veins are always the last parts of the leaves to lose their green color (chlorophyll). The brown spots are the final stage of iron deficiency, just before the leaves fall and leave bare branches. It might be possible/affordable to inject the trunk with iron to turn the tree around, but it’s going to have to be done regularly. You could also try ground applications of an iron supplement combined with sulfur to help lower the soil’s pH, thereby keeping the iron in a soluble form. But it’s going to be a huge and challenging hill to climb.
Dear Neil: We have two cherry laurels that have been in our landscape for about a year. They are not doing too well (see photos). How can we improve their health and vigor?
A: Each of the trees got too dry one or more times. If they were my trees, I would prune them back to compensate for the roots they lost in that process, and then I would really water them deeply once a week for the next 12-15 months. Apply a high-nitrogen fertilizer now and again in early April. Incidentally, cherry laurels also show iron deficiency in alkaline soils (basically, the western 80 percent of Texas). Nellie R. Stevens hollies might be better choices across all of the state.
Dear Neil: We bought a house that has a loquat that has grown to 8 to 9 feet tall. It’s too close to the house, and we want to trim it back. When should we do that? It produced a lot of fruit this year.
A: First things first — that’s not really big for a loquat, so if you’re thinking about pruning it back very far, you’re really going to be penalizing it. You might want to consider relocating it instead. But pruning and relocating are both done in mid-winter. Just try not to remove more than 20 to 25 percent of its growth. Rapid regrowth fosters fire blight bacterial infection.
Dear Neil: We have a very large bur oak that has been shedding a great deal of fuzz all summer. It seems like the maintenance level has ramped up. Love the tree. Not so happy with the maintenance of picking up fuzz, leaves and twigs. Any suggestions?
A: I’ve never had many complaints of this before, but several this summer, both here and on my Facebook page. I do not have it on my several large bur oaks, so I haven’t seen it first hand. It might be leafhopper frass/fuzz (harmless), or it may just be natural pubescence from the bur oak (also harmless). In either case. I’d suggest just blowing it into a pile so you can clean it up and moving on. You have one of the finest large shade trees for Texas. Any other tree will have other faults, and most of those will be much worse.
Dear Neil: Any idea what might be wrong with my Meyer lemon?
A: I do not profess to be an expert on citrus, but looking closely at the information in Texas A&M’s Plant Disease Handbook, which also covers many insect pests, this looks like it might be citrus leafminer (Phyllocnistis citrella) damage. I’m going to let you take it from there. TAMU and the University of Florida have excellent reference information online.
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.