Why are my red oak trees struggling?

Danielle and Mike Demarest are having some trouble with three well-established red oaks in their backyard. For the past several years, one has struggled, barely has any leaves at all, and is just overall stunted. An arborist ruled out oak wilt, but didn’t have any other real answers.

Danielle and Mike further report that when they bought their home several years ago, the soil around the trees was covered with weed barrier and pea gravel. Since we didn’t see any obvious signs of disease or insect problems, we consulted Paul Johnson, with the Texas Forest Service on this one, who also expressed his expert opinion that there was no evidence in the photos of any particular pest damage.

With the background information regarding the weed barrier and pea gravel around the trees earlier in their history, Paul noted that soil compaction and other soil/root issues, such as girdling roots, are most likely the underlying causes for this tree’s decline.

Although potentially, but less likely, herbicide damage or the last stages of bacterial leaf scorch could also be at play.

Unfortunately, this situation provides an opportunity to point out that our first thought when we notice struggling plants is to assume a disease or insect issue. That’s a natural inclination, since we want to believe that we can potentially address those issues and remedy the situation, thus saving the plant and getting it back on track.

But more often than not, environmental issues that are difficult if not impossible to control, especially when we inherit an older landscape, are at the root of the problem.

Danielle and Mike also say that they’ve removed the pea weed barrier and pea gravel and replaced them with wood mulch to hopefully alleviate the issue, a great first step, and I must commend you for correctly diagnosing the most likely problem and taking the best possible course of action to potentially remedy the situation.

If the tree’s not too far gone, one other step that might help would be to aerate the soil around your trees with an air spade. But you’d need to hire an arborist to perform that service, and it’s not a guarantee of success, so I would suggest that you consult several companies before you go to such an expense.