The Hidden Reasons Hydrangea Leaves Develop Holes

When hydrangea leaves develop holes, most gardeners immediately start searching for beetles, caterpillars, or some other hungry insect. You turn the leaves over, check the stems, and look around the soil—but there’s nothing there. The damage is obvious, yet the culprit seems to have disappeared.

That doesn’t necessarily mean insects aren’t involved. Many pests feed at night, hide during the day, or leave the plant before you notice the damage. In other cases, what looks like chewing may actually be caused by leaf spot, rough weather, or damage that occurred while the leaf was still unfolding.

The shape, location, and color around the holes can tell you quite a bit about what happened. Before spraying your hydrangea with an insecticide, take a closer look at the clues.

Why Hydrangea Leaves Develop Holes Without Visible Bugs

There are two basic ways holes form in hydrangea leaves.

Something may physically eat or tear through the leaf. However, a damaged or diseased section of leaf tissue can also turn brown, dry out, and fall away. That second type of damage can leave a hole that looks surprisingly similar to insect feeding.

The most common hidden causes include:

• Night-feeding slugs, snails, caterpillars, and earwigs
• Four-lined plant bugs
• Leaf spot damage
• Japanese beetles that have already moved on
• Hail, strong wind, or heavy rain
• Damage to tender leaves while they were unfolding
• Accidental damage from tools, hoses, or nearby branches

Instead of treating every hole the same way, try to identify the pattern first.

Night-Feeding Pests May Be Hiding During the Day

One of the simplest explanations is that the pest is active when you aren’t looking.

Slugs, snails, earwigs, and certain caterpillars often feed after sunset. By morning, they may be hiding beneath mulch, rocks, pots, boards, or fallen leaves around the base of the hydrangea.

Slugs and snails usually leave irregular holes with rough edges. You may also notice a shiny or silvery trail across the foliage, stems, mulch, or nearby ground.

Earwigs can create small, ragged holes while hiding in cool, damp areas during daylight hours. Caterpillars may rest along stems, beneath leaves, or inside leaves they have folded or tied together.

Inspect the hydrangea shortly after dark with a flashlight. Look beneath the leaves and around the base of the shrub rather than checking only the most damaged areas.

Four-Lined Plant Bugs Can Create a Shot-Hole Effect

The four-lined plant bug is easy to miss because it can feed quickly and move away when disturbed. Young plant bugs puncture tender leaves and remove plant juices, leaving small, dark, sunken spots.

As the injured tissue dries, the center of the spot may fall out. This creates a pattern that looks as though the leaf was peppered with tiny holes.

The University of Minnesota Extension notes that four-lined plant bug damage can produce brown, black, or translucent spots before the dead tissue falls away and creates a shot-hole appearance.

This type of damage commonly appears on tender spring growth. By the time the holes become noticeable, the insects may have matured or moved on.

Learn more about identifying this damage through the University of Minnesota Extension’s hydrangea diagnostic guide.

Leaf Spot Can Make Hydrangea Leaves Develop Holes

Not every hole was chewed.

Hydrangeas are susceptible to several leaf spot problems, especially during warm, wet, or humid weather. Spots may begin as purple, brown, black, or tan areas on the foliage. As the affected tissue dies and becomes brittle, part of the center may crack or fall away.

This is more likely to be leaf spot than chewing when you see:

• Brown, purple, or yellow borders around the holes
• Spots and holes appearing together
• Damage beginning on lower leaves
• Yellowing or early leaf drop
• Symptoms becoming worse after rainy weather
• No droppings, slime trails, webbing, or visible pests

If your hydrangea also has dark spots, our guide to black spots on hydrangea leaves explains how to recognize common leaf diseases and reduce future problems.

Leaf spot often looks worse than it is. A healthy, established hydrangea can usually tolerate a moderate amount of damage without losing its ability to grow or bloom.

Japanese Beetles May Have Already Left

Japanese beetles can cause dramatic leaf damage in a short period. Rather than making only a few isolated holes, they often eat the softer tissue between the veins. This leaves behind a thin, lace-like or skeletonized leaf.

The beetles are usually easy to see while they are feeding, but they don’t remain on one leaf forever. They may fly away when disturbed or move among several plants throughout the day.

Look for:

• Leaves with veins remaining but tissue missing
• Groups of damaged leaves near the top or outside of the plant
• Similar damage on roses, crape myrtles, grapes, or other nearby plants
• Beetles appearing during warm summer weather

Check the plant during the morning, when Japanese beetles are often slower and easier to remove. Hold a container of soapy water beneath the leaf and gently knock the beetles into it.

Caterpillars Can Hide Better Than You Think

Small caterpillars often blend into stems and leaf veins. Some feed from the underside of the leaf, making them nearly invisible when you inspect the plant from above.

Hydrangea leaftier caterpillars create an especially noticeable clue. They pull two newly emerging leaves together with silk and feed from inside the protected space. You may see tightly joined leaves near the end of a stem rather than an exposed caterpillar.

Gently separate suspicious folded leaves and inspect the inside. Removing the affected leaves by hand is often enough when only a few stems are involved.

Avoid spraying the entire shrub until you know what you are treating. Broad insecticide use can harm beneficial insects without solving the real problem.

Hail and Wind Can Tear Hydrangea Leaves

Weather damage can look remarkably similar to insect feeding.

Hail may puncture leaves, bruise tender growth, and leave random holes across several plants at the same time. Strong wind can whip large hydrangea leaves against branches, fences, plant supports, or neighboring shrubs.

Weather damage is more likely when:

• The holes appeared suddenly after a storm
• Several kinds of plants have similar damage
• Leaves also have tears, bruises, or shredded edges
• Stems or flowers show signs of impact
• No new holes appear after the weather improves

There is usually no treatment necessary. The existing holes won’t heal, but healthy new foliage should emerge normally.

Young Leaves May Have Been Damaged While Unfolding

Sometimes the injury occurs before the leaf reaches its full size.

A tiny puncture, insect feeding spot, frost injury, or scrape on a folded young leaf may stretch into a much larger hole as the leaf expands. By the time you notice it, the original cause may be long gone.

This often explains why several leaves have holes in similar positions or why the damage looks stretched rather than freshly chewed.

Inspect the newest growth. If the fresh leaves are healthy and the damage isn’t spreading, the problem may already be over.

Accidental Garden Damage Can Leave Lasting Holes

Hydrangea leaves are broad and relatively soft. They can be damaged by more than pests and disease.

Common sources of accidental injury include:

• Dragging a garden hose through the shrub
• String trimmer or mower debris
• A nearby branch rubbing against the leaves
• Rough handling during planting or pruning
• Pets moving through the planting bed
• Strong streams of water
• Sprays applied during hot or sunny weather

Mechanical damage usually appears randomly. It won’t continue spreading unless the source of the injury remains.

Look around the plant for anything touching, rubbing, or striking the foliage.

How to Diagnose the Damage Before Treating It

When hydrangea leaves develop holes, spend a few minutes gathering clues before applying anything.

Examine both sides of several leaves, including leaves that have only recently begun showing damage. Check the stems, folded leaves, and the mulch beneath the shrub.

Look for:

• Slime trails
• Caterpillar droppings
• Fine webbing
• Folded or tied leaves
• Dark borders around holes
• Skeletonized tissue
• Scraped leaf surfaces
• Similar damage on nearby plants

Inspect the hydrangea again after dark. A nighttime visit often reveals pests that remain hidden during the day.

Take a few pictures and compare the plant every several days. Old holes remain visible even after a problem has stopped, so the best sign of an active issue is the appearance of fresh damage.

Should You Remove Leaves With Holes?

A few damaged leaves usually don’t need to be removed. They can still photosynthesize and help support the plant.

You may remove a leaf when it is:

• Mostly destroyed
• Heavily spotted or diseased
• Folded around an active caterpillar
• Yellowing and beginning to fall
• Blocking your view of an active pest problem

Don’t strip the shrub bare just to make it look cleaner. Removing too many leaves can place more stress on the hydrangea than the original damage.

For more help comparing discoloration, spots, wilting, and pest symptoms, visit our guide to common hydrangea leaf problems.

How to Prevent More Holes From Appearing

The right solution depends on the cause, but good plant care makes hydrangeas less vulnerable to several problems.

Water at the base whenever possible and water early enough for wet foliage to dry before night. Keep mulch a few inches away from the main stems, and remove heavy layers of decaying debris that provide hiding places for slugs and other pests.

Give the shrub enough room for air to circulate. Crowded, constantly wet foliage encourages leaf spot and provides sheltered conditions for hidden insects.

Continue inspecting the plant rather than automatically spraying it. Hand-picking pests, removing a few folded leaves, or correcting a rubbing branch may solve the problem without stronger treatment.

When a pesticide is truly necessary, identify the pest first and select a product specifically labeled for that pest and for use on ornamental shrubs. Follow the label exactly.

Will the Holes Disappear?

Existing holes won’t close or fill back in. Once hydrangea leaf tissue is gone, that part of the leaf remains damaged for the rest of the season.

That doesn’t mean the plant is continuing to decline.

Watch the new growth instead. If fresh leaves are opening normally and no additional damage appears, the cause may have passed. Hydrangeas can tolerate a surprising amount of cosmetic leaf damage while continuing to grow and bloom.

When Hydrangea Leaf Holes Are a Serious Problem

A few scattered holes are rarely an emergency. You should investigate more closely when:

• Fresh damage appears every day
• Most of the shrub is becoming skeletonized
• Leaves are rapidly yellowing or dropping
• Dark spots are spreading throughout the plant
• New growth is distorted or failing to open
• The plant is also wilting despite adequate soil moisture
• Multiple hydrangeas are affected

Severe leaf loss reduces the plant’s ability to produce energy. A young, newly planted, or already stressed hydrangea may need more attention than a mature, well-established shrub.

Final Thoughts

When hydrangea leaves develop holes, the missing insect may simply be feeding at night, hiding beneath the foliage, or no longer present. The damage could also come from four-lined plant bugs, leaf spot, Japanese beetles, hail, wind, or an injury that occurred while the leaves were still unfolding.

Look at the pattern before reaching for a spray. Ragged edges suggest chewing, discolored borders may point toward dead leaf tissue, and widespread sudden damage may have come from the weather.

Most importantly, watch for fresh damage. Old holes can make a hydrangea look troubled long after the original problem has ended. If the newest leaves are healthy and the shrub is growing normally, it will usually be just fine.