How to Get Rid of Japanese Beetles on Roses

How to Get Rid of Japanese Beetles on Roses

Roses have long captivated people with their distinct colors, beauty, and difficulty to grow. The upper class of the Victorian era even created an entire language of flowers with roses at the center to express their emotions when they otherwise could not. It is no surprise, then, that many modern individuals now choose to have rose bushes and blooms grow in their gardens to add extra elegance and beauty to the landscape.

Unfortunately, roses can be quite frail and susceptible to their environment. Amateur gardeners often have trouble keeping the bushes healthy because of poor soil, bad trimming, or the ever-present pests that are attracted to the blooms. If you have a rose bush, the most common pest you’ll have to deal with is the Japanese beetle, a veritable scourge that rains down upon gardens like a plague of locusts.

If you’re tired of Japanese beetles, check out this quick guide to get rid of them on roses. 

How to Get Rid of Japanese Beetles

It’s important to know your enemy. When it comes to roses, the Japanese beetle hasn’t been a threat for long. While they are native to Japan, most ecologists believe the beetles arrived in the United States around 1912 in a shipment of iris bulbs. They then spread quickly, reproducing and resulting in the modern ecological issue seen today. 

What Is a Japanese Beetle?

As the name suggests, the Japanese beetle is a beetle characterized by an iridescent brown and green shell. They are known to prey on over 300 different plants, but roses are their favorite food. They are believed to do over $540,000,000 worth of damage each year just to established industries, with little known about the destruction wrought on the natural development of plants. 

Each beetle is between 8 and 11 mm. long with small white patches of hair at the edge of their backs. The main reason why they are an issue is because the beetles can reproduce rapidly and leave grubs behind for the next generation of flowers. They also have no natural predators in the United States, while those in Japan do. This means the population can grow out of control rapidly since nothing is eating the beetles or their grubs.

Effective Methods for Roses

There are natural and synthetic (chemical) methods to eliminate the beetles that roost and feast on roses. One of the most effective options for amateur and professional gardeners alike is the use of a pesticide that attacks Japanese beetles while they are grubs. Some products, like the eponymous Milky Spore, can be applied to the soil around rose bushes. When the grubs hatch, they eat the pesticide and slowly die. Other beetles then become affected by the spores left behind by the corpses. The result is the destruction of the population before they eat your roses, and with no detrimental effect on the flowers.

In addition to the pesticide for grubs, you can also use a basic insecticide for the adults. It is unrealistic to expect every grub to be affected, especially since the beetles could be traveling to reach your roses. Most insecticides to target Japanese beetles can be sprayed on or around the rose bush without damaging it. These work in a variety of ways, but many will poison or desiccate the beetle so it dies almost immediately after exposure. 

How to Get Rid of Japanese Beetles on Roses

If you do not like chemical treatments, there are still some options. One of the most basic is almost ridiculously simple: Pick the beetles off your flowers. The Japanese beetle is notoriously slow, and they can be removed by hand in the morning and tossed in a bucket of soapy water so they drown. I used to do this all the time as a kid to help my mom in the garden.

You can also try to plant some repulsive – to the beetles – herbs in the garden. Catnip, chives, and garlic are quite effective, but they won’t work as well as more chemical methods. You also might need to keep the neighborhood cats out of the garden. 

What Not to Do

The internet is unfortunately filled with misinformation, especially when it comes to pest control. While you might be desperate to save your roses from the scourge of the Japanese beetle, there are still some steps to avoid. One of the most important things to do is to avoid the use of common household products in your rose garden. Roses are delicate flowers, and using dryer sheets or laundry detergent around them is likely to cause decay and death from chemical exposure.

Besides keeping the laundry in the laundry room, you should also avoid the patented “Japanese beetle traps” currently on the market. A study conducted by the University of Kentucky indicated the traps actually attract more beetles than they kill. The result is roses plagued by pests and beetle corpses littering the soil. Other plants nearby can even become affected, laying host to tons of beetles.


Finally, don’t wait to take action. The best treatments for Japanese beetles need to be implemented early in the insect’s life cycle, so you need to address the problem before it gets out of hand. Remember, it is better to be cautious than foolhardy. 


Japanese beetles can be a vicious threat to your rose garden, especially if you have never encountered them before and begin the season unprepared. After all, the most effective method to deal with these pests is to plan ahead and spread an insecticide around your rose bushes before the beetle season begins. If you get the right one, you can even stop their spread, growth, and development with a single application.

Beyond using pesticides, you can utilize more natural methods like your hands, soapy water, and even plants like catnip. If you choose these methods, though, they tend to be less effective than pesticides. However, they can lead to healthier roses in the long run, so be sure to do your research before picking a method.