Dear Neil: What is this very fine webbing that is all over the trunk of my live oak?

Answer: I wondered if we were going to get any questions on these this year. These are called bark lice, although they’re not really lice at all. Entomologists name them Cerastipsocus venosus. They live within the fine webbing around the trunks of several species of trees, commonly live oaks, where they perform the somewhat beneficial act of cleaning the trunks of funguses, algae and dead bark. Treating for them is not recommended. Consider them a novelty, probably beneficial and move on.

Dear Neil: The past two years this oak tree hasn’t been dark green except for the area on the right. The largest part has been yellow, and now leaves are turning brown and falling off. I’ve tried iron, but it didn’t help. What can I do?

Answer: I can’t tell from the photo what type of oak you have, but it may very well be a species that needs acidic soil (therefore with soluble iron). Adding iron to species like pin oaks, water oaks and willow oaks in alkaline soil will be futile. The only other explanation I would have would be that there might be trunk or root damage on the side of the tree that has dropped leaves so conspicuously. You might want to have a certified arborist look at it, but it’s going to be hard to turn it around. This is definitely iron deficiency.

Dear Neil: This gorgeous palm is now blocking the entry to my backyard. How can I trim it without damaging it?

Answer: You’re going to have to cut the offending stems out selectively, but honestly, I wonder if it wouldn’t be better just to reroute the walk a bit to the left? Do you have room to do that? It looks like the railroad tie is beginning to deteriorate a bit. That might solve both issues.

Dear Neil: I have xeriscaped much of my front yard because of the shade being tough on the lawn – plus, I like the effect. But does St. Augustine grow in long shoots like I’m seeing, or is that an invasive weed?

Answer: All I’m seeing in the photos is St. Augustine runner trying to cover in the shade. You’re going to need to switch over to a shade-tolerant groundcover. St. Augustine won’t make it without a lot more sun.

Dear Neil: This hibiscus came up from seed this spring in a pot of begonias. Obviously, it’s very happy. Should I just cut it back? I don’t know what to do with it.

Answer: Hmm. It’s unusual for a tropical hibiscus to sprout up from a seed like that. I assume you’ve seen flowers on it, and the foliage certainly looks like it matches. Yes, before winter, I’d cut it back by half to fit it into a greenhouse or sunroom better. That’s assuming I’d decide to save it.

Dear Neil: I am having an increasingly bad problem with winter grasses. When I put pre-emergent down at the end of September, I had a terrible problem. When is the proper time to apply pre-emergent granules? Do I need three applications for year-long prevention?

Answer: Late September is definitely way too late. The application of Dimension, Halts (now called Weed-EX) or Balan should be made between Aug. 25 and Sept. 5. I’m willing to slide the deadline back by a couple of days to include the weekend through Sept. 8. And your spring applications for crabgrass, grassburs and other summer grassy annuals are made about two weeks before the average date of your last killing freeze for your part of the state, with a follow-up treatment 90 days later.

Dear Neil: My bermuda front lawn looks terrible. I water it carefully, but it doesn’t seem to help. What am I missing?

Answer: This is either Pythium cottony blight or bermudagrass mites. I just can’t be sure from one photo, although I suspect Pythium. It’s usually a disease of “prosperity.” It moves into bermuda turf that has been over-fertilized and kept too wet. Bermuda mites are microscopic. They cause very short internodes (stems between leaves) resulting in the look of an old-fashioned shaving brush. I don’t see that in your photo. I would encourage you to research each of those online. Clemson University has good information on each.

Dear Neil: Why would one pair of star jasmine plants have died like this when the other is still doing well?

Answer: I’ve never seen any insect or disease bother either Asian jasmine or star jasmine. Therefore I’ll rule them out. My guess would be something more exotic like a plugged drain hole or a build up of mineral salts in the soil. It’s definitely some kind of problem with the root system or it wouldn’t have affected the entire pair of plants like this. Do a little more investigating and you can probably determine the cause of the problem.

— Have a question you’d like Neil to consider? Mail it to him in care of this newspaper or e-mail him at mailbag@sperrygardens.com. Neil regrets that he cannot reply to questions individually.