Quote from Lee Garden Ninja on 8th April 2025, 12:24 pm

Hi @kateh

Thanks for your question about what's munching on your Azalea leaves, and looking at it, it's either leaf cutter bees if in mid summer, given the very neat edges, or the Azalea caterpillar if in spring, which munches the leaves before pupating and turning into butterflies.  Both of which are part of our wider gardening ecosystem. So my first advice would be don't panic, they won't kill the azalea, and actually you're providing a much-needed food source for wildlife, so ten ninja points there. 

However, I also know that people tend to panic when a shrub is being ravaged. As long as shrubs are not completely stripped bare, then they nearly always recover.

What's Eating My Azaleas and How to Stop Them?

Let's take a look at the common causes and treatments for azaleas that are being munched with holes appearing on their leaves. Understanding what’s behind the Azalea damage and how to tackle the problem can help restore your azaleas to their former glory.

Common Culprits of Eaten Azaleas

1. Azalea Lace Bug
These tiny, dark, shield-shaped insects are a big problem for azaleas, especially in hot, dry conditions. Both the nymphs and adults suck sap from the undersides of leaves, causing a stippled pattern of pale spots and a general decline in leaf health. If you spot black spots or fine webbing on the underside of leaves, it’s a sure sign of an azalea lace bug invasion.

2. Japanese Beetles
These metallic green and copper beetles are notorious for eating holes in the leaves of azaleas, leaving behind a skeletonized leaf. If you’ve seen them munching away during the warmer months, then you've likely encountered these pests. They are particularly active in the summer and tend to leave plants looking quite battered.

3. Spider Mites
While not technically insects, these tiny arachnids are known for causing a lot of damage. Spider mites feed on the cells of azalea leaves, causing them to yellow and develop a speckled appearance. If you notice fine webbing along with the discolored leaves, you’re probably dealing with a mite infestation.

4. Slugs and Snails
When the weather is damp, these slimy critters come out to feast on azalea leaves, leaving behind ragged holes and a trail of silvery slime. They tend to be more of a problem in the early spring and fall when the weather is wetter.

5. Caterpillars
Certain caterpillars, particularly those of moths, will happily munch on azalea leaves, often leaving behind irregular holes or completely defoliating a branch. The culprit might be the caterpillar of the Lonomia obliqua, which can cause significant damage if left unchecked.

How to Stop Them

1. Hand-Picking and Trapping
One of the simplest and most eco-friendly methods is to hand-pick pests like Japanese beetles, slugs, and caterpillars. For beetles, try catching them in the evening when they’re less active, and simply squish or drown them in soapy water. For slugs and snails, you can lay out beer traps—small containers buried at ground level filled with beer to attract and drown them.

2. Natural Predators
Encourage natural predators to your garden! Birds, frogs, and hedgehogs love feasting on insects like Japanese beetles and slugs. You can attract these helpful creatures by creating a wildlife-friendly garden with bird baths, hedgerows, and ground cover. The best option though is to consider adding a wildlife pond to your garden and let wildlife balance out the pests for you!

3. Diatomaceous Earth
For slugs and snails, diatomaceous earth is a great natural option. This fine powder is made from the fossilized remains of tiny aquatic organisms and acts like shards of glass to the soft bodies of slugs and snails, causing them to dehydrate and die. Sprinkle it around the base of your azaleas for protection.

4. Chemical Controls
While it’s always better to go natural when possible, chemical controls can be effective if the situation is dire. However, I can't in good conscience recommend them as they are often misapplied and cause havoc for waterways, wildlife and other plants.

The Benefits of Letting Wildlife Munch Certain Plants

While it might seem like a good idea to protect your azaleas from every single pest, there’s a case to be made for letting nature take its course. Many pests, such as caterpillars, snails, and even certain insects, are part of the local ecosystem and play vital roles in maintaining biodiversity. Here’s why sometimes it’s okay to let a few leaves get nibbled:

1.Balanced Ecosystem
By allowing some natural predation, you help create a more balanced garden environment. For example, caterpillars might be munching on your azaleas, but those same caterpillars will feed birds and provide nutrients to your soil when they break down. Plus, a healthy population of natural predators (like ladybugs and birds) can help keep pest numbers in check without your intervention.

https://youtu.be/GWHtKKyU3eQ

2. Encouraging Beneficial Insects
Pests like aphids and spider mites are often eaten by beneficial insects such as ladybugs and lacewing larvae. By allowing these pests to thrive, you're indirectly supporting their natural predators, which can help keep your garden healthy in the long run.

3. Encouraging Pollinators
Some of the pests you see on your azaleas, like certain beetles, are also important pollinators. Allowing them to visit your plants means that you’ll also be helping the pollination process for other plants in your garden. After all, the world of plants and insects is deeply interconnected.

4. Better for Soil Health
When you leave some plant damage in your garden, it encourages the natural decomposition of plant matter. This can improve soil health, as broken-down plant material becomes compost and provides vital nutrients for your other plants. The occasional nibble here and there isn’t always a bad thing—it’s part of nature’s cycle!

While it's important to protect your azaleas from the worst pests, don’t be afraid to embrace a little wildlife-induced munching. In many cases, a few holes in the leaves are a small price to pay for a healthy, balanced ecosystem. By encouraging natural predators, using eco-friendly controls, and understanding the importance of biodiversity, you can keep your azaleas—and the wider garden—thriving all season long.

Do let us know how you get on.

All the best

Lee Garden Ninja