What is Eating the Leaves on My Knockout Roses?

Although Knockout Roses are incredibly resistant to insects and animals, there are still some that like to feed on its leaves and flowers. The key to defeating them is to find out what they are and to have the right solution on hand. This article will answer the question, ‘What is Eating the Leaves on My Knockout Roses?’

What is Eating the Leaves on My Knockout Roses?: Insects 

What is Eating the Leaves on My Knockout Roses?

The list of insects that can eat away at your knockout rose leaves include the following:

  • Leafcutter Bees
  • Rose Slugs
  • Japanese Beetles
  • Sap Suckers

Leaf-Cutter Bees

Standing at less than an inch, these insects eat knock out rose leaves in a half-circle pattern on the edge. They use it to build their nests and generally do no great harm to the plant.

Rose Slugs

Rose slugs aren’t slugs per se- they’re sawfly larvae that attach to the underside of knockout rose leaves. The adult stage is the most damaging as they can eat through foliage quickly.

Japanese Beetles

What is Eating the Leaves on My Knockout Roses?

They’re instantly recognizable with a blue-green head and copper back. When left unchecked, Japanese beetles will eat leaves wholesale, and you’ll be left with a knockout rose that’s not aesthetically pleasing (nor healthy).

Sap Suckers

What is Eating the Leaves on My Knockout Roses?

These are a group of tiny insects, including scale, thrips, mites and aphids. You’ll want to keep an eye out for them as they could kill your knockout roses and transfer diseases to your other plants.

How to Treat Knockout Roses For Insects


To treat sap suckers you’ll want to regularly apply commercial insecticidal soap on a weekly or bi-weekly basis. Make sure you follow instructions on the label or bottle and spray the solution to the leaves and its undersides as well.

Insecticidal sprays also take care of rose slugs as well. You can treat your knockout roses the moment you see aphids and similar pests so they won’t affect your plant in the long run.

For heavy infestations you’ll want to apply every week to try and get rid of the problem.

You won’t need to address leaf-cutter bees as they’re generally beneficial to the environment. The damage they do is minimal and only on the leaves themselves.

Natural Remedies

The best way to eliminate insects landing and staying on your knockout rose is a jet of water to dislodge them. Check for the presence of pests on the top and underside, then direct a spray of water in an effort to knock them off your plant.

Alternatively, you can pick off Japanese beetles by hand or allow the ones with white spots on them to visit your roses, since the eggs they leave will keep away the beetles and kill them.

Animals that Like to Eat Knockout Roses

The list of animals that are most likely to eat Knockout Roses include the following:

  • Deer
  • Rabbits
  • Squirrels

What Animals are the most likely to Eat Knockout Roses

Deer, squirrels and rabbits consider knockout roses to be fair game. Once they gain entry they will eat away not just the leaves but all its parts, including the flowers and stems.

These animals tend to favor tender growth and shoots, so if you see chunks and gnaw marks on your plants then it’s likely that they’re the culprit.

How to Stop Animals from Eating Knockout Roses

Prevention is the best way to keep animals away from your yard or garden. You can install a fence around your roses or combine them with plants they don’t like, including marigolds and herbs such as rosemary, thyme and mint, just to name a few.

In general, you’ll want to tidy up your yard or garden every now and then. Remove debris and weeds so you can easily spot them and they won’t have a reason to stick around.

Remove close-hanging branches where squirrels could travel across to your rose. Do some pruning and remove canes that are in contact with each other as they tend to attract pests.

Deer repellent can deter animals away from your knockout roses. You can buy one commercially or create them on your own.

This tends to prevent rabbits from approaching as well, so you’re essentially solving two problems with one solution.

What is Eating the Leaves on My Knockout Roses?: Final thoughts

Lastly, you can use neem oil to deter animals from eating your knockout rose and its leaves. Follow directions and make sure to spray the underside as well.