I’ve been answering gardeners’ tree questions for 54 years. I thought you might enjoy seeing some of the more interesting ones.

Why is bark falling off my crape myrtles?

That’s normal. Horticulturists refer to it as “exfoliating” bark. Sounds dermatological. The reason it happens is because bark is a dead tissue that can’t expand as a tree’s trunk grows larger. All it can do is pop off in pieces and fall to the ground. Crape myrtles, sycamores, paper birches and a few other species just happen to do it in large sheets of paper-thin bark. Other trees shed much smaller chunks. Either way, it’s a normal occurrence and no cause for concern. New bark is being formed just inside it.

Why is bark falling off my live oaks in big sheets?

At first glance one might think this is a variation of the very same question, but this one is quite different. This is the result of injury due to extreme cold. Arborists call it “radial shake,” and it refers to the bark popping loose from the phloem and other internal layers. We saw it following the terrible cold spell of February 2021, and we Texans actually lost 10% or 15% of our live oaks. Many of the trees lost only a portion of their bark, and those trees are struggling to recover. All we can do is wait and watch, although you may want to hire a certified arborist to ensure that the tree doesn’t come tumbling down unexpectedly.

Why is the bark splitting on the trunk of my red oak?

That’s almost always due to sun scald, and it’s almost always on the west or southwest side of the trunk. That’s where the summer sun hits the tree when it’s first planted. The tree was shaded by other trees in the nursery, but suddenly it’s out in full sun. The damage shows up after two or three years, and by then it’s too late. If you have a newly planted red oak, red maple (Acer rubrum) or Chinese pistachio, apply paper tree wrap from the ground up to its lowest limb immediately to protect it. Leave it in place for one to two years.

Will English ivy growing up a tree’s trunk harm the tree?

Probably not. The vine is only using the tree’s trunk for support. Its roots cling to the bark, but they do not penetrate the wood to pull water or nutrients out of the trunk. The only ways the ivy will cause problems will be if it grows out on the branches and shades the canopy, or if it adds enough growth to the branches that its evergreen leaves could add weight during an ice storm. You’ll always be safe if you keep it pruned to a manageable height solely on the trunk itself.

Do roots appearing on the surface of the soil beneath my tree indicate erosion? Put in other terms, should I add soil to cover them?

No to both. The old axiom is that 90% of a tree’s roots are in the top foot of soil. To some degree, they mirror the limb growth. Branches of most trees are relatively horizontal, live oaks being a classic example. As the live oak grows larger, its branches do, too. And as the branches grow larger, so will the roots. Those that were originally only 3 or 4 inches below the surface of the soil will enlarge until they grow up and out of the soil.

There are mature live oaks in southeast Texas and along the Gulf Coast with massive buttressing roots 2 and 3 feet in diameter. There has been no erosion, so there is absolutely no call to add soil. In fact, that would be very harmful to those trees.

Leave surface roots alone. If one or two threaten your foundation or sidewalk, cut and remove it in the fall, but do so when they’re still small (less than 2 or 3 inches in diameter for a 15- or 20-inch tree).

What is causing rows of holes in my tree’s trunk?

Holes that are in rows are caused by woodpeckers and sapsuckers. Unless they are repeatedly hammering the same tree at the same level, they will do no permanent harm to the tree. More serious damage happens occasionally to hollies and other smaller trees, but rarely to others.

Still, you will see the effects of their work on pecans, oaks and other shade trees. Don’t let it worry you. They generally are drilling their holes, then coming back later to feed on the sap that flows from the tiny wounds. If you feel you must, apply pruning sealant across the holes. Otherwise, just keep an eye on things. The bird will eventually move on to other targets.

Are root-feeding rods a good way to water and feed my trees?

They are fine as long as you don’t push them more than a few inches into the soil. Remember what we discussed earlier: 90% of a tree’s roots are in the top foot of soil. Those rods will tempt you to insert them too far. You’ll miss most of the roots.

Similarly, poking holes in the ground and filling them with fertilizer puts way too much plant food in a concentrated area and none just a few inches away. It’s much better to do a surface application followed by a heavy watering.

Are the water bags around trees’ trunks a good idea?

For small, first-year trees, perhaps, but after that, not in my eyes. A tree’s roots extend out as far as its branches (the “drip line”), which is why you’ll see the recommendation of watering around the perimeter where the feeder root growth is most active. Soaking the trunk does almost no good. Plus, how many people are willing to fill those bags daily? That’s how much water it would take to meet the needs of growing trees. Nope. No thanks. Give me a soaker hose I can spiral out around that drip line.