Rose leaf spot

Asked May 21, 2018, 11:10 AM EDT

We recently moved into a home with some beautiful roses. I would like to cut the roses and bring them inside for flower arrangements. However, the tea roses have leaf spot. Is there an environmentally-friendly treatment for this? Are there precautions to take when cutting or pruning the roses in order to avoid spreading the condition from one plant to another?

Marion County Oregon roses leaf spot

5 Responses

When you reply to this email, please send at least 3 images to help us diagnose the problem. Preferred are (1) the plant and its surroundings; (2) the plant; and (3) a close view of a branch with normal and affected leaves.

If you have more than 3 pictures you think will be useful, attach them to another reply.

I look forward to receiving your pictures.

Thank you, Jean! Attached are three photos of the rose bush, which gets full morning sun and afternoon shade.

Ann Moore

Jean, here is a fourth picture which may also be helpful. Thank you!

Ann Moore

Ann,

Thank you for the images. It's just as I suspected but had to be certain in order to suggest the correct management. The disease is black spot of roses.

Black spot of roses is a very common disease in our region. Successful management requires cultural tactics as well as periodic sprays.
  • Keep leaves as dry as possible. Avoid overhead watering.
  • Ensure good air circulation. (Unfortunately, a site adjacent to a house or fence limits air circulation.)
  • Sun exposure for at least 6 hours a day, more is better.
  • Remove and destroy infected plant parts.
  • Consider replacing the roses with a ore resistant kind but, at the same time, know that all roses will have black spot to some degree.
Sprays are effective if applied at bud break (when the rose begins to grow) and periodically thereafter. If you want to spray, you can choose from multiple brand name products available at large independent garden centers.

Thank you very much, Jean! We will shop for some more resistant varieties, but we will also trim and spray the ones we have.

Ann