The beauty of your roses can be easily overcome by diseases and fungi. As roses are more delicate when it is cold, they are more likely to fall to diseases when the seasons turn warmer.
Even if they get through winter relatively unscathed, their weaker immune systems will be more open to the heat and humidity that the spring rains and summer heat bring. In this way, the roses might contact a fungal infection that destroys them, despite all of your best efforts.
You will probably find some common types of illnesses associated with your roses:
Powdery Mildew
Powdery mildew is a fungus. As its name suggests, a white powder is produced along the stems as well as on both sides of the leaves. If you do not treat the mildew right away, the rose will not reach its full potential and the leaves will start to die and fall off the plant.
Rust
Rust on roses looks just like rust on metal will. It appears on the underside of the leaves and quickly spreads to other parts of the plant as well.
Blackspot
Hybrid teas are completely resistant to blackspot, but other roses have been known to get it. If there are circular black spots on the leaves of the plant that are 1/16 to ? inch in diameter, you might have the disease. Treat the disease right away to avoid destroying your plant's foliage.
Rose Mosaic
Unlike most of the rose diseases that are fungi, the Rose Mosaic disease is a virus. The symptoms of this disease are similar to what you would expect from the name with discolored mosaic patterns of yellow and green.
The only way to stop this from spreading throughout your garden is to remove the plant entirely. You will also need to remove all of the leaves and clippings from the affected plant to ensure that it does not get to your other species. If you cannot stop the effects of this disease, you will need to bring in professional help and ask about commercial treatments that will solve the problem.
How can you avoid giving your plants these diseases? There are a few things you can do. Always water the soil around the rose and not the rose itself. Clean your rose beds regularly to prevent fallen leaves from cluttering underneath. Snip off the stricken blooms and discard them immediately. Prune regularly. Close all cuts in the plant with Elmer's glue. Feeding your roses regularly will also give them plenty of strength to fight infections.
Finally, you can choose disease-resistant roses whenever possible to avoid the problem in the first place. Having plants that are naturally resistant to diseases and fungi will help your other plants as well since you will not be harboring any potential problems and threats in your garden.
