Rose Disease – BlackSpot

One Of The Most Common Rose Diseases

What Causes It:  

  • Heavy Rainfall
  • Splashing Water on rose leaves during watering
  • Mold spores and fungus left over from previous years or from general neglect

Common Black Spot On Rose Petal

How To Treat It:

  • In the dormant season (when roses are not growing) apply a dormant spray such as Lime Sulphur. Spray the rose bed and the entire bush. This will kill any fungal disease lurking about.
  • During the growing season, (especially the show season) I spray my roses every 10 days with a fungicide. There are several kinds on the market. Some earth friendly, some not. I have used Manzoceb, a chemical spray for several years with good results. This year, I began using “Green Cure” fungicide which has no harmful chemicals on my miniature roses, and have also had good results.
  • If you have a real problem with Blackspot. It’s ok to spray two times per week, remembering to remove any diseased leaves each time. The blackspot should clear with in 10 days. 

Prevention is the key! My Mama used to tell me, it’s better to “prepare and prevent”, than to “repair & repent”.

  • Keep your rose beds free of fallen leaves and other garden debris
  • Always water roses from the base of the plant. Never the top.
  • Remove all diseased leaves from your roses. Blackspot is a fungus and will quickly spread.If you will employ these practices in your rose garden, your roses will thank you for it!

9 Responses to Rose Disease – BlackSpot

  1. Wonderful article and a great product I have been told and now I’m sold <|;-)


    • Thanks Annie! As you know I’m trying to keep it natural and not be a harm to our environment as much as possible. your soil conditioners have helped my roses put down strong healthy root system. The stronger the roots, the healthier the bush. It’s great to be in the garden with you!


  2. Lara Lewis says:

    Great info! I’m going to try Green Cure. Thanks Chris!


  3. Chris,

    I think GreenCure works like baking soda in that it’s a broad spectrum fungicide. There are a lot of beneficial fungi in the soil that I think also get harmed. It’s still better than using other fungicides.

    Have you ever tried using cornmeal? I’ve used it a few times in my lawn to deal with disease and it worked well for me. One person even uses it for black spot on roses with success.

    I wrote a post about cornmeal for lawn disease that contains a lot of the information I’ve gathered related to how it works and what disease it might help with.

    Since you have so many roses maybe you can use one as a test next year to see if it works for you? It needs to be applied directly on the soil. One year I got some on the mulch and a little bit of slime mold developed.

    I wasn’t big on compost tea but I’ve been starting to change my mind. Good compost and possibly compost tea applications are other options for disease control. Heck, compost seems to cure almost any garden problem. Before next year I’ll likely make my own compost tea brewer.


  4. Ross says:

    I leave in Italy, I am thinking to Buy 3 Don Juan rose climber , but , I should to know as and if its. flower changes with the sun .for e campale , does its color change from red to purple? Is important for me bacasse I need a climber rose red and not purple . Thank you for your reply .


  5. Alistair says:

    Hi Chris
    Thanks for an informative article. I too have written about rose black spot and thought you might like to take a look. Let me know what you think?


  6. Diane Dunlap says:

    Why would my Julia child roses blooms turn pinkish?


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