Question
Hi Lynnette, I am still struggling with black spot on my knockouts, I thought it was under control because the new groth was clear and they were blooming beautifully but the 100 degrees and the muggy nights brought it back. At what temp. can I spray safely? My main question is black mulch. I am currently using it under the roses and other shrubs but I was told the dye in the mulch would damage them. Is this true? The brand name was naturescapes and there was no warning of this problem on the bags. If so, should I remove it now? Thanks again for your help,Betty

Answer
Naturescape mulch is a product made by Scotts. This is a reputable manufacturer and I really doubt that they would jeopardize their good name by putting out a garden product that would damage plants. I think I would have faith in their product. However roses usually like a little space around the base of their canes so you could move some of the mulch away if it is touching the stems. This applies to all mulches and it helps the water to seep under the mulch. As you have described, it was the perfect weather for black spot and as the spores are in the air there is really nothing you can do. I am sorry to hear that your Knock Outs got it badly, as this rose is said to be almost disease free. What th roses are telling you is that they will always get black spot in those conditions. Sometimes we may love a rose but it isn't the rose for our location and weather conditions. There are so many roses I would love to grow, but in my poor soil with gale force winds, the answer is a loud no.