How can I stop the black spots on my roses?

Question

I live in a humid climate and I'm having trouble getting blooms and good foliage.

Answer 1

Karma,
Many good suggestions thus far. Ortho and Bayer make good sprays for the mold. The fert is a great idea. I'm going in a different direction ( in a way ).
You need to remove the leaves/stems with the Black Spotting ASAP. Use a hand pruner to do this. Before you prune mix 1 cup of Clorox bleach to one gallon of water in a bucket and put on a pair of latex or rubber gloves. After each cut (yes it is a pain in the....) dip the pruner and the gloves in the solution. This will prevent spreading the disease.
Remove any/all mulch from the base of the plant to an area outside the dripline of the plant. The spores can/do live in this environ. With the pruner cut all lower branches and sprouts to six-eight inches above ground (allows for air). Replace the mulch with a shredded Cypress Mulch. This is not cheap, however, it looks great and suppresses the molds.
The fert is the great idea. You want an acidic fert that has a ratio of 1-2-1. This would translate into a 5-10-5, 10-20-10 etc. You want this to be Granular and spread from about two or three inches from the base to a foot outside the dripline of the plant. This will promote the root growth. You will apply before remulching and water it in deeply. Fert the shrubs every six-eight weeks. Since they are in stress there is nothing wrong with using the liquid Mir-Gro Acid immediately on the pruning and remulching.
There is a simple spray you can use to greatly reduce the problem. Put 1 cup per gallon of Pure Ivory Liquid Detergent in a sprayer (adapt to the amount you really need.). Spray the underside and upperside of the leaves and the stems as well. Do this when the temps are not expected to be above 75-78 and apply in the morning when it can dry. Organic without the cost! Hope it helps.

Answer 2

Look for a spray that says on it -kills black spots. There are different brands- I know Ortho makes one. I've been having the same problem with my rose bushes!

Answer 3

I use Miracle grow for Roses to fertilize
and
Orthos ....Orthenex insect and disease control
for Roses and flowers and shrubs.
http://www.ortho.com/index.cfm/event/ProductGuide.product/documentId/223c71ef02f2c70cd9f52244e6600b7a
Where to Use
Roses, flowers and ornamentals.
What It Controls
Aphids, whiteflies, mealybugs, budworms, mites, leafminers, thrips, scales and other listed pests.

(Also protects roses against black spot, rust and powdery mildew diseases.)
I use the spray can it's easier to get all of the leaves