Thanks for writing. Do you water your roses with a sprinkler? If so, using soaker hoses or just letting a hose sit on the ground and drench it so the leaves stay dry may help a bit. How closely are your roses growing together? Good air flow helps cut back on the disease, so pruning or transplanting so there's abundant airflow between the branches should help.
If your roses seem to get black spot every year no matter what you do, it may be that the varieties just aren't suited to your climate. Choosing varieties known for their disease resistance or that are particularly well suited to your region should also help. Learn more here: http://www.bhg.com/gardening/flowers/roses/how-to-save-roses-from-black-spot/