Common Rose Diseases

There's nothing worse than seeing all of your hard work destroyed by a rose disease or fungus. Roses can be weakened during the winter dormancy and become more susceptible to disease when the growing season begins.

Even if the bush survived winter unscathed, spring rains and summer's heat and humidity can open the door to a variety of fungus infections.

Here is a summary of the most common diseases which could pose a threat to your roses.

Powdery Mildew

This is a fungus disease that produces a white powder along the tops and bottoms of the leaves and along the stems. Left untreated the plant will not grow to its full potential and the leaves will die and drop off.

Rust

Rust looks like an orange powder which appears on the underside of leaves and will spread to other parts of the plant.

Blackspot

Hybrid teas are blackspot resistant, but many other varieties are susceptible.  The disease appears as circular black spots on the plant's leaves which range between 1/16 to 1/2 inch in diameter. Left untreated, blackspot will destroy your plant's foliage.

Rose Mosaic

Unlike most rose diseases, which are fungal in nature, Rose Mosaic is caused by a virus. Symptoms generally resemble discolored mosaic patterns and yellow and green.

The only treatment is to remove the infected plant from the garden. Make sure that you also remove all leaves and clippings which fall from the affected plant.

If you are unable to stop the spread of fungus-based diseases by simply cutting back the affected areas, see you garden supply professional and ask about commercial fungus treatment products.

You can reduce the chances of your roses being affected by fungus if you follow these tips:

Always water the soil around the rose plant and never water the plant itself.

Clean your rose beds regularly and remove all clippings and fallen leaves.

Cut any diseased canes or blooms and dispose of them in your trash can.

Practice regular pruning and pay special attention to pruning out the center of the bushes to allow air to circulate.

Seal all cuts. Elmer's Glue works fine. It's safe, effective and inexpensive.
 
Feed your roses regularly. Wee-fed roses are better able to resist infection.

Choose disease-resistant roses whenever possible, especially if you live in areas with high heat and humidity. Remember that disease-resistant does not mean disease-free. It simply means that there is a less likely chance of the plant becoming infected if you follow all of the tips that you read here.