black spots on roses?

Answer 1

I've been growing roses for years and have recently discovered that 3 tablespoons of Apple Cider Vinegar to 1 gallon of water sprayed on the infected roses is wonderful. Not to mention that it is inexpensive and harmless. I'd been using commercial products with minimal success and since using the vinegar the black spot appears to have stopped in it's tracks. Vinegar changes the pH of the rose leaf and the black spot can't live at a high pH. Remove all the really nasty looking leaves and make sure you clean up the leaf debris from the soil including the mulch. Add new mulch and then spray your roses once a week with the AC Vinegar solution until the growing season is over. As a preventative you can start using the solution next season just as soon as your roses leaf out. Oh, it's also very important to water your roses early in the morning and at the base as another preventative measure. Good luck

Answer 2

Milk is effective : 1 part milk to 9 parts water

Alternate the following sprays. These seem to work best as preventatives rather than corrections. By altering the pH of the garden the opportunity for fungus to take hold is lessened. Spray early in the morning before the temperature begins to rise above 75 degrees so as not to cause burning of the foliage
Baking Soda
Mix 1 oz. of baking soda with 1 gallon of water and spray the foliage and soil in the morning to retard fungus. This will make the pH more alkaline.
White Vinegar
Mix 1 oz. of white vinegar with 1 gallon of water and spray the foliage and soil in the morning to retard fungus. This will make the pH more acidic.

Wettable Sulphur
Mix 1 oz. of wettable sulphur with 1 gallon of water and spray the foliage and soil in the morning to retard fungus. Sulphur will leave a yellow residue on the foliage sprayed

Add cornmeal to the soil.Texas A&M has been testing corn meal and found that corn meal works by feeding and stimulating a fungal species (in the genus Trichoderma) that feeds on other (non-beneficial) fungal species. In one trial, they found that after spreading yellow corn meal, the Trichoderma build up destroyed vast amounts of non-beneficial fungi. They further found that the level of control with corn meal is influenced by 1) soil moisture, 2) temperature, and 3) pesticides used (or not used). Applications of certain synthetic chemical based fungicides inhibited Trichoderma, which would limit the usefulness of corn meal.*

Good luck! Hope this helps.

Answer 3

pluck off the leafs with the black spot. Then got to your local garden store, and buy a fungus killer. and spray them once a week. Keep doing this until the black spot is gone

Answer 4

Go to Lowe's or Home Depot & buy the Ortho powder that is used to sprinkle on roses. Ask someone if you aren't sure what's best.