Ask Burton: Q: I have two live oaks in my front yard that were planted 6 years ago. When they were planted, they were both three-inch diameter trees. One has grown robustly, it’s somewhere between seven and eight inches through the trunk now. My other live oak might have grown half as much and doesn’t look nearly as good. The trees are getting the same water, fertilizer, and light. Can you tell me why this one is having a problem growing?

A: There are other possible answers, but a very likely answer is a buried root flare. Look closely at the base of the trunk where it meets the soil surface. What you’d like to see looks something like the root flare in this picture.

If the tree’s trunk does not widen at least a little at ground level, your tree is planted too deeply in ground. There are several common planting errors that can cause this – placing soil on top of the root ball at planting, too many voids beneath the root ball after planting that collapse after a few waterings, oversized watering rings slumping soil over the root ball over time, or, most commonly, too much soil is placed on top of the root ball to plant flowers around the tree.

Excess soil above grade slows and stunts the growth of your tree, and interferes with how well the tree can root into the area. If your root flare is not visible at grade, dig down and remove however much soil is necessary until you do see a more natural flaring near the base of the tree. Mulch can be applied to cover the area afterwards, but not soil. While digging, examine the root flare closely; if there are any roots wrapped around the base of the flare or if there’s wire or nylon twine around the base, cut those free of the trunk. If roots are embedded, a single vertical slice (even if you cut into the trunk) will help in removing them. This will help you to get the most out of your trees.

Don’t let your trees get to THIS point! It was too late for this tree to recover. Â