Question
QUESTION: Thank you for printing the information about clay soil and roses.  I live in Florida-zone 9 (Hernando) (we can get down to 20 some evenings in the winter). Our soil is sandy soil.  We planted our roses in a mixture of southern peat moss, top soil and manure.  We have sprinklers that go on automatically by our community for an hour a week.  We water in between.  I have black spot on most of my roses-in two different locations.  It must be me doing something wrong!!  Do you think I should follow the directions for the lady whose letter you answered?

Tks so for the help!

ANSWER: You speak of an answer that I gave but I am afraid I can't find it. Questions come in to me and I answer them and then they are put in the past answer list which you have access to. I would rather answer all questions on an individual basis because what is a good answer for a gardener in New york will not be the same as someone in Florida. You have rose problems that someone in California never has. The main problem you have is a climate that encourages black spot in roses.
Overhead watering is fine as long as it is only done in the morning and when it is hot or sunny. Any other time means that the leaves stay damp and that is what the black spot fungus needs to start it's life. Also in a black spot prone area, a gardener needs to select roses carefully as some are prone to this fungal disease. Colours such as orange, orange reds, apricot, yellows and even some whites seem to attract problems quicker than the other colours. Again in your area, roses need to be in full sun as part shade can also keep the leaves damp. In the perfect garden one would only water once every 5 days and then make sure the water went down to at least 5 inches. As this is not always possible you have to do what fits your garden's location.
Have a look at your roses and see if the colour has any meaning in regards to the disease. I too garden on sandy soil and I know that a sprinkler on for an hour really doesn't get down far enough. As you have said, you also water in between so you are probably getting down enough but you only really need to water every 5 days. Roses once established are really quite drought resistant.
A mulch helps with black spot as roses love cool roots and do much better with any type of a mulch around the base.
I have left out spraying until the last because some gardeners prefer not to spray. If you don't mind spraying then any rose spray for black spot will do the job if you constantly spray. Here is a tip for you if you don't want to spray. To keep black spot under control, all you really need is to make a rose leaf inhospitable to the fungus. That means making the leaf less acid. Rose spray will do that but you can also have some success with spraying your roses with a foliar spray such as Alaska Fish fertilizer or any other organic type of foliar spray. This will also fertilize your roses too. I only suggested the Alaska Fish because it is cheapest. After spraying when a fungal spore lands on the leaf it hasn't got the conditions it wants and so won't develop. When roses get disease or go wrong, never blame yourself, because in your area it is not an easy job to grow roses without any problems. Hope this helps.

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QUESTION: Thank you so much for the help!!  I have always heard that Knock Out Roses were virtually 'fool' proof!!  Unfortunately-our water goes on at 9 p.m. once a week for an hour-and I know that is a problem.  I didn't realize that my question wasn't posted next to the last question-so apologize for the clarification being unclear.  Can't thank you enough for the information, and will do as you suggest!!!

Answer
The advertising regarding Knock Out roses is very impressive but I get an awful lot of questions complaining about them. I think it would be impossible to demand that any rose be bullet proof when conditions for disease are perfect. Under ideal conditions where other shrub roses would also do well, Knock Out roses do very well even better but when the conditions are not, poor old Knock Out roses get rose problems too. Good luck.