Roses are gorgeous; I can’t think of any other flowering plant in my garden that always stops me in my tracks every time I go near them. They are quite easy to grow, if you follow certain guidelines but they do have a weak spot; roses get diseases.
Roses diseases need to be spotted early so check them daily, for me this is never a chore, I never get bored of looking at my roses. Look for anything out of the norm; dark spots appearing on leaves, buds only partially opening if at all, petals turning brown and mold developing. Do look on the canes and stems as well, checking that they aren’t discolored.
Study this subject in depth, learn all there is to know about these types of fungus; botrytis blight, canker, balling, dieback, crown gall and blackspot. Remove any infected parts and destroy totally, making sure to clean out the cut thoroughly with a water chlorine mix; 1 part chlorine to ten parts water will do. Remove the plant and relocate if a better spot can be found, if you want to leave it where it is, remove as much of the soil where it was growing, destroy and replace with uninfected soil.
I would only recommend using an organic treatment spray and this is what I use but don’t mix it in the kitchen if you like a peaceful household:
Chop a medium strength chilli pepper, a few cloves of garlic and an onion and place in a pan with about a liter of water. Heat up but do not boil and leave for an hour. Strain this liquid through a coffee filter and then add a teaspoon of baking soda. You will end up with a concentrate so dilute in a spray bottle with four times as much water as concentrate. This will not only help prevent disease but will also repel most pests and people too! There are many different recipes for making your own treatment spray, you should research and experiment with others to find the one best suited to you
Inorganic Disease Treatment
These are now widely available from general stores and nurseries and they can be very effective but it is best to think of them as a short term solution. They can easily affect negatively the balance of your rose plant and the soil it grows in, damaging organisms and bacteria that your rose needs, so if you do have to use one do so sparingly