Why are my tree's leaves curling?
Leaves cupping, twisting, puckering, or growing narrow and strap-like — usually the newest growth, sometimes only on one side of the tree.
Watch it, correct the care behind it, and check again next season. Nothing here threatens people or property in its current state.
Most curl is either an insect on the new growth or the tree folding its leaves to survive a hot afternoon, and neither threatens an established tree. The version worth documenting rather than ignoring is herbicide injury, because it tends to repeat every season and because the source is usually something you or a neighbor can stop doing.
What this looks like
Distortion means the leaf was interfered with while it was still expanding, so the pattern preserves a record of what happened weeks earlier. Cupped leaves curl in like a shallow bowl. Herbicide-affected growth twists along its axis and often develops parallel veins that fan out instead of branching normally. Insect curl is tighter and rolled, usually at the shoot tip, and something is living inside it.
- Cupping or downward curl on the newest leaves while older leaves further back are normal
- Narrow, strap-shaped or fan-veined new leaves — the signature of growth-regulator herbicide
- Tightly rolled shoot tips that unroll to reveal aphids, or leaves stuck together with silk
- Bumps, pouches, or fuzzy patches on the blade that are firm rather than soft
What causes it in Kansas
Roughly in order of how often each turns out to be the answer here. The line under each one is what separates it from the others — open a cause for the detail.
1Herbicide drift and vapor
How to tell: Twisted petioles, cupped or fan-veined new leaves, damage strongest on the side facing the treated area, and often more than one species in the yard showing it at once.Growth-regulator herbicides — 2,4-D, dicamba, and their relatives — are used on Kansas lawns, roadsides, and crop ground, and they move both as spray droplets and, on hot days, as vapor long after application. Trees do not have to be sprayed directly to be affected.
2Aphids on new growth
How to tell: Unroll a curled tip and find soft-bodied insects, cast skins, or sticky residue inside.Colonies feed at expanding shoot tips, and the leaf curls around them as it grows. Common on maple, hackberry, elm, and honeylocust in Kansas, and usually resolved by lady beetles and lacewings within a few weeks.
3Eriophyid mites and gall makers
How to tell: The distortion is a discrete structure — a bump, pouch, or velvet patch — rather than a general curl of the whole blade.Microscopic mites cause fingerlike growths, felty patches, and puckering, most conspicuously on hackberry, maple, and elm. They look alarming, they are extremely common in Kansas, and they cost the tree essentially nothing.
4Heat and water stress
How to tell: Leaves are curled at four in the afternoon and flat again at seven in the morning, with no distortion in the veins.Leaves fold or roll along the midrib to reduce the surface exposed to sun and wind. It is a working response, not damage, and it reverses overnight when temperatures drop.
5Late frost injury
How to tell: Only the earliest leaves are affected, growth produced after the frost date is normal, and you can trace it to a specific cold night in April.A hard freeze after bud break kills part of an expanding leaf, and the surviving tissue keeps growing around the dead area, producing puckered and misshapen leaves.
What to do, and what to avoid
Safe to check yourself
All from the ground — no ladder, no saw.
- Unroll several curled leaves and look inside before deciding anything
- Check whether the newest growth above the damage came in normal, which dates the event
- Ask what was sprayed nearby, and when — including a neighbor's lawn service and adjacent crop ground
- Look at other plants in the yard; tomatoes and grapes show herbicide injury earlier and more obviously than trees do
What not to do
The responses that make this one worse or permanent.
- Do not spray an insecticide for what turns out to be herbicide injury — you will add a stress and fix nothing
- Do not prune off distorted growth right away; damaged leaves still photosynthesize and the tree needs them
- Do not apply weed-and-feed products inside the drip line of a tree you care about
- Do not spray herbicide on a still, 90-degree afternoon, which is when vapor movement is worst
When to contact an arborist
Whatever this narrows it down to, the assessment that decides what happens next has to happen at the tree. Why that is
Common questions
Will the tree recover from herbicide drift?
Will the tree recover from herbicide drift?
A single mild exposure on an established tree is usually outgrown by the following season. Severe or repeated exposure is different — it can kill branch tips, deform the crown over several years, and leave the tree vulnerable to borers. The variable that matters is whether it keeps happening.
Do I need to treat the galls on my hackberry?
Do I need to treat the galls on my hackberry?
No. Hackberry nipple galls and the woolly aphids that come with them are permanent features of growing hackberry in Kansas. No practical spray program controls them on a mature tree, and none is warranted.
Why are only the top leaves curled?
Why are only the top leaves curled?
The top of the crown is where the newest growth is and where the most sun, wind, and drifting spray arrive. Symptoms that concentrate at the top are ordinary for both herbicide and heat, but top-only symptoms that persist into the next season point at something else — start with dieback at the top of the tree.
Kansas Tree Guide is an independent educational resource. Nothing on this site replaces an on-site assessment by a qualified arborist or tree-care professional. Last reviewed August 2026.
Often seen alongside this
A second symptom narrows the cause faster than more detail about the first.
Not what you are seeing? Work the symptom guide again.