Common Rose Problems and How to Cure Them
Roses are one of the most beautiful and alluring gifts in all of nature, but just like anything else that’s good, there’s always something out there to destroy it.
At gardening info, we know most varieties of roses are highly susceptible to fungus, pests and disease, except the Knockout Rose, which was bred to resist disease and pests. With a little work and persistence, you can have delightful roses that are free of bugs, fungus and disease.
Black Spot Fungus
Like the name sounds, Black Spot covers your rose foliage in tiny black spots that grow bigger and bigger. The fungus lives in debris that piles up under your roses, so keep your gardens clean and free of debris. Humidity and wet conditions seem to play a factor as well, so try to only water the ground and not the rose’s foliage.
To cure black spot:
- Clean up all debris scattered in your rose beds.
- Remove all infected foliage and place in a closed container (not out in the yard or in your compost).
- Use a fungicide like powdered sulfur if the Black Spot persists.
After you prune your roses, always disinfect your sheers with rubbing alcohol.
Black Spot Fungus
Powdery Mildew
Like Black Spot, Powdery Mildew is caused by a fungus that lives in debris piles under your roses. Powdery Mildew looks like someone came by and threw baby powder all over your roses – except there’s nothing good about it!
The cure for Powdery Mildew is essentially the same as other rose fungal infections:
- Clean up all debris scattered in your rose beds.
- Remove all infected foliage and place in a closed container.
- Use a fungicide like powdered sulfur if the problem persists.
A homemade remedy is to spray a mixture of 1 teaspoon baking soda, 1/2 teaspoon canola oil and one quart of warm water.
Powdery Mildew
Rose Rust
Another fungus roses are prone to is Phragmidium, which causes strange orange-red discolorations on the rose leaves that looks like rust. Rose rust usually begins on the bottom and moves to the top.
Not to sound like a broken record but…
- Clean up all debris scattered in your rose beds.
- Remove all infected foliage and place in a closed container.
- Use a fungicide like powdered sulfur or a homemade baking soda spray if the rust persists.
Rose Dust
Japanese Beetles
Did you know that grub worms grow up to become Japanese Beetles? Grub worms live underground, eating grass roots, which can result in large patches of dead grass.
Japanese Beetle Grubs
Japanese beetles are characterized by their shiny coppery-green husks and their poor flying ability. They love to munch on rose plants as a group, making huge holes in leaves and then moving onto the next.
- Your first line of defense is to shake them off and pull them from your roses and drop them into a bucket of soapy water.
- For bad invasions, spray organic insecticides as needed.
- To kill them in their larval stage, use milky spore powder on your lawn.
Adult Japanese Beetles
Aphids
Aphids are tiny green bugs that slowly eat small holes in your rose’s foliage. While hard to see, you’ll notice teeny tiny holes that seem to get bigger over a week or so.
Aphids come in large numbers, but due to their light green color, they blend in easily. Your first step to stop the aphid invasion is to remove the foliage where the aphids have congregated and throw it away in a closed container.
If the aphids have spread beyond a few leaves, your best bet is to spray a mixture of water, liquid dish soap, and canola oil. This solution is harmless to your plants yet makes it hard for the aphids to breathe.
Another innovative aphid treatment is ladybugs! While we might think of ladybugs are harmless little bugs, they’re actually the #1 predator to aphids.