Why Your Tree's Leaves Turn Brown in Mid-Summer

Brown leaves in July and August almost always mean the tree cannot move enough water to its canopy, and the fix depends on which part of that system failed: dry soil, damaged roots, or a trunk that was buried too deep years ago. It is not the tree starting fall early. Deciduous trees drop leaves in autumn after a controlled shutdown, and that process looks nothing like the crispy, edge-first browning you see in high summer.

Augusta summers push this hard. Long stretches of high heat, heavy clay soils that hold water poorly in a drought and stay soggy after a storm, and afternoon sun that pulls moisture out of a leaf faster than roots can replace it. A tree that looked fine in May can show brown margins within a week of a dry spell, especially a young one or one planted in the last two or three seasons.

The pattern of the browning tells you more than the color does. Where the brown sits on the leaf, and where it sits on the tree, narrows the cause fast.

Brown along the leaf edges and between the veins, spread evenly across the whole canopy, points to water stress. Brown patches on one side of the tree only usually point to a root or trunk problem on that side. Browning that starts at the top and works down can mean the root zone is compromised. The table below sorts the common patterns.

Walk the drip line, the outer edge of the branches, and push a screwdriver or a hand trowel into the soil there. If it will not go in without real effort, the tree is dry at the depth that matters. If the soil is wet and stays wet days after rain, the roots may be suffocating, and the leaves brown for the same reason: the roots cannot do their job.

Five causes cover most mid-summer browning in this part of Georgia: drought, heat and sun scorch, root damage from digging or grading, trunks buried too deep, and damage to the trunk or a major limb. Drought is the most common and the easiest to rule in or out.

• Drought. Roots need moisture in the top foot or so of soil. A short heavy shower runs off clay and does not soak in. Weeks of that and the canopy starts to brown from the edges inward.
• Heat and sun scorch. Leaves on the south and west sides of a tree take the worst of the afternoon sun. Thin-barked young trees and trees that lost lower branches to pruning are more exposed.
• Root damage. Digging a trench, adding a patio, regrading a yard, or driving equipment over the root zone severs the fine roots that absorb water. The canopy shows it weeks later, often on the side where the work happened.
• Buried trunk. A tree planted too deep, or one that had soil or mulch piled against the base, slowly loses the bark at the root flare. That damage can take years to show up as browning.
• Trunk or limb injury. A mower strike, a string trimmer, a storm crack, or a wound from an old removal nearby can cut off water to part of the canopy.

Insects and disease exist in this region too, but they are less often the first explanation for browning that appears across a whole tree in a dry stretch. If the pattern is one limb or one side, look at the trunk and roots before you look for a pest.

Water slowly and deeply at the drip line, and check the soil with your hand before you water again. Deep, infrequent soaking beats a daily sprinkle. For a mature tree, that means running a hose on low at the outer edge of the canopy for a long stretch, moving it around, and letting the top several inches dry slightly before repeating. Mulch helps, but keep it a few inches back from the trunk and no more than a couple of inches deep.

Do not fertilize a tree that is browning from drought. Fertilizer pushes new growth the tree cannot support and can make the stress worse. Do not prune brown leaves off in mid-summer to tidy the tree; those leaves are still shading the branches beneath them. Do not assume the tree is dead because the canopy looks bad. Scratch a small spot on a twig near the tip with your thumbnail. Green underneath means that wood is still alive and the tree has a chance.

Hold off on major pruning until the dormant season unless a limb is broken, hanging, or over a structure. Summer pruning of a stressed tree removes stored energy it needs to recover.

Call for an assessment the same day if the browning comes with a lean that was not there before, a crack or split in the trunk, mushrooms at the base, or a hollow sound when you knock on the lower trunk. Those signs mean the question is no longer cosmetic. A tree that is dying back from the top with a compromised base can fail without warning, and in a windstorm that is a danger to the house, the car, and anyone underneath.

What makes a removal harder, and what we look at before quoting one, is the space around the tree. A clear drop zone changes the job a great deal compared with a trunk hemmed in by a fence, a power drop, or a roof line. Access for equipment, the height and lean of the trunk, how much of the canopy hangs over something you cannot damage, and whether the wood can be dropped in sections or has to be rigged down all move the work. The number itself needs an on-site look at the tree and the ground around it; we will not put a figure on a removal from a photo.

If the tree is still alive and the problem is water or roots, the answer may be care rather than removal. If the trunk is failing, the answer is removal, and waiting through another storm season is the riskier choice.

Treat it yourself if the browning is even across the canopy, the soil is dry, and the trunk is sound. Have the tree looked at if the browning is one-sided, if the trunk is damaged or the base looks wrong, or if the tree leans or has dead wood over anything you care about.

If you are not sure which column you fall in, the soil test and the twig scratch take five minutes and tell you most of what you need. Everything else can wait for a look at the tree in person.