Black Spot On Roses

Learn what black spot is, how it affects roses, and what you can do to prevent and get rid of it.

Roses are one of the most beautiful flowers found in gardens across the globe. They are also known to be among the most difficult to care for. Blackspot is a common problem that plagues roses. Learn how to identify, prevent, and treat blackspot on your roses.

WHAT IS BLACKSPOT?

Blackspot is a fungus that looks like black spots of different shapes and sizes on the leaves of a rosebush or plant. The affected leaves will eventually turn yellow, brown and fall off. One-year-old canes can be infected too. They develop raised purplish-red spots of different shapes and sizes. Eventually they become black.

Although blackspot can only be transmitted by water droplets, it can survive winters on infected canes and old infected leaves under the plant. When a plant becomes wet and stays damp for at least seven hours, blackspot can develop. It will begin at the lower leaves of the plant and work its way up during the warm growing season. If a plant is severely infected, all foliage could disappear. It is indeed an unsightly problem.



PREVENTION

There are several ways to prevent blackspot from attacking your rose plants. First, determine if the plant's site is appropriate. For example, does it have enough air circulation around it to dry off after a soaking rain? Perhaps a grouping of rose bushes is spaced too close together. Consider transplanting them further apart to increase air circulation among the plants. Make sure the site you choose received plenty of sunlight.

Second, don't water late in the day. If the sun has gone down for the day and you've just watered your roses, chances are that's enough for the fungus to infect your plant. Remember that when you do water your roses don't soak or mist the foliage. Try to water at the ground level.

Third, when fall comes and you're cleaning up the garden, remember to rake up any remaining leaves that have fallen from your rose plant. They may not be infected, but clearing them away from your plant greatly reduces the chance that blackspot will strike the next Spring. Don't compost any infected material because you could redistribute the fungi.

Fourth, when purchasing roses, try and choose resistant cultivars. Unfortunately, there aren't many, but there are a few. Check out your local nursery and discuss your choices with them. While you're there, take a look at their selection of preventative fungicide sprays for spring application. This will greatly reduce the chance of your plants becoming infected.

TREATMENT

When your roses have blackspot there are a few things you can do to treat them. Remove infected leaves because they will drop anyway. Choose an appropriate fungicide and use according to label instructions. You may have to spray periodically throughout the growing season depending on what type of fungicide you choose. During the fall, prune dead or infected canes from your roses so the fungi cannot overwinter and survive.

STOP AND SMELL THE ROSES

You can take time to stop and smell the roses when you take a little extra time with them. You'll be greatly rewarded with beautiful fragrant blooms and healthy plants overall.

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