="http://i243.photobucket.com/albums/ff43/tnashudson/flowers/roses003.jpg" border="0" alt="Purple rose">

Does anyone know what gets rid of these black spots?

 Black spots are usually a fungus infection. Try baking soda and dish soap in a sprayer.

Water the gsoil instead of the plant. You want to keep the leave as dry as possible.

Thanks I'll try it.

How long does it take to work?

Aslo if it is already infected just remove the leaves and keep it away from the plant to keep it from reinfecting the plant.

One other thing you can do is put banana peels at the base of your plant. It's good for the rose because it provides potasium and keeps the aphids away.