Japanese beetles on shrubs can cause noticeable damage quickly, especially when large numbers gather on the same plant.
Well, that’s not a fancy new garden texture. There’s a good chance Japanese beetles have moved in and helped themselves to lunch.
Quick Answer
The simplest way to control Japanese beetles on shrubs is to check plants regularly and knock the beetles into a container of soapy water, especially early in the morning when they’re less active. Avoid placing Japanese beetle traps near susceptible plants because they can attract additional beetles. For severe infestations, use only an insecticide labeled for Japanese beetles and follow the label carefully.
Japanese beetles are shiny, metallic-looking insects that usually show up during the summer. They can gather in groups and feed on leaves, flowers, and even fruit. If you do not catch them early, they can make your favorite shrubs look pretty rough in a short amount of time.
The good news is that you do not always have to grab the strongest pesticide on the shelf. A few simple steps can help reduce the damage and protect your plants.
About Bobby & Lynn
How to Identify Japanese Beetle Damage
Japanese beetles are fairly easy to spot once you know what to look for. Adult beetles have metallic green bodies, copper-colored wings, and small white tufts along the sides of their bodies.
The damage is often even easier to recognize. Japanese beetles eat the soft tissue between the veins of the leaf. This leaves behind a thin, skeleton-like pattern. In heavier infestations, leaves may look brown, scorched, or almost transparent.
Plants that may attract Japanese beetles include:
Roses
Crape myrtles
Fruit trees
Grapevines
Berry plants
Japanese maples
Flowering shrubs
Not every plant will be equally attractive to Japanese beetles. A landscape with a good mix of shrubs, flowers, and trees is usually less vulnerable than a yard filled with only one type of plant.
Remove Japanese Beetles by Hand
For small gardens and backyard landscapes, hand-picking is one of the easiest ways to control Japanese beetles.
Fill a small bucket or container with water and add a little dish soap. Walk through the garden and gently knock the beetles into the soapy water. The soap helps keep them from escaping.
This method works best in the morning when the beetles are often slower and less active. Check your shrubs regularly, because new beetles may show up even after you remove the first group.
It may not be the most glamorous garden chore, but it is simple, cheap, and does not require spraying chemicals on blooming plants.
Be Careful With Japanese Beetle Traps
Japanese beetle traps are easy to find in stores, but they are not always the best choice for a small yard.
These traps use attractants to pull beetles toward them. While they may catch a lot of beetles, they can also draw more beetles into your yard. Some of those beetles may stop and chew on your shrubs before they ever make it to the trap.
If you decide to use a trap, do not place it beside the plants you are trying to protect. Put it far away from your favorite shrubs, garden beds, roses, and crape myrtles.
The University of Georgia Extension guide to Japanese beetles also notes that traps are better used for monitoring than for protecting plants because they can attract large numbers of beetles without preventing feeding damage.
Keep Your Shrubs Healthy
Healthy shrubs are better able to handle minor insect damage. Water your plants deeply during dry weather, add a proper layer of mulch, and keep weeds from stealing moisture and nutrients.
Avoid overfertilizing damaged shrubs during extreme summer heat. Too much fertilizer can push out soft, tender new growth that may attract more feeding and require more water.
You can also prune away severely damaged or diseased branches when needed. Use clean pruning tools and avoid removing too much foliage at one time, especially when the plant is already stressed.
If you’re dealing with leaf damage on hydrangeas too, our Hydrangea Help page has guides for identifying common hydrangea problems, pests, watering issues, and other causes of damaged leaves.
Use Insecticides Carefully
If Japanese beetles are causing serious damage and hand-picking is not enough, an insecticide labeled for Japanese beetles on ornamental plants may be an option.
Always read and follow the product label carefully. More product does not mean better results. It can harm the plant, nearby pollinators, and beneficial insects if it is not used properly.
Be especially careful around blooming shrubs. Bees, butterflies, and other pollinators may be visiting the flowers. Avoid spraying blooms while pollinators are active. If the shrub is covered in flowers, try hand-picking first when possible.
What About Japanese Beetle Grubs?
Adult Japanese beetles are only part of the problem. Their larvae, called grubs, live in the soil and feed on grass roots. Large numbers of grubs can damage lawns.
However, treating the lawn does not guarantee that adult beetles will stay off your shrubs. Adult beetles can fly in from nearby yards, fields, and other areas.
If you are seeing lawn damage along with heavy beetle activity, contact your local extension office for advice on the best grub-control options for your area.
Check Your Garden Regularly
Japanese beetle damage is much easier to manage when you catch it early. During summer, walk through your garden every few days and check the leaves and flowers on your shrubs.
Pay close attention to roses, crape myrtles, fruit trees, and any plants that have been damaged in the past. Removing a few beetles early is a whole lot easier than dealing with a crowd later.
Final Thoughts
Japanese beetles can be frustrating, but they do not have to ruin your garden.
Start with the simplest method first. Check your shrubs often and knock beetles into a bucket of soapy water. Keep your plants watered, mulched, and healthy so they can handle minor damage better.
Be cautious with traps and insecticides, especially around blooming plants. With a little consistency, you can reduce Japanese beetle damage and help keep your flowering shrubs looking good through the summer.
