Start with more information. Where on the rose are they? Where are you located? What has the weather been like? How many leaves are affected?

They just look like old leaves to me, but need more data.

Just a few scattered about. Semi- coastal So. Ca. where the weather has been pretty perfect. I suspect/ hope it is just old leaves, and the nature of rose bushes....small sacrifice to pay for those luscious blooms. But later into summer they can get pretty vile, which I'll try to prevent this year with better mulching and water observation. This is a common complant?

Wow! Thanks to roseseek, I believe I have an answer!! This is from another thread: ".....My experience in all of them has been drip irrigation is simply not sufficient in the average conditions. Water doesn't "just" keep the plant hydrated. It is also the mechanism to permit the soil to "breathe". As water soaks through the soil, filling the air spaces between the soil particles, it pushes out the carbon dioxide released by the plant roots and bacterial and fungal actions in the soil, and draws air (oxygen) into them behind it. "Drips" of water which infrequently fill those air spaces often don't provide that function. Many soils and most water contain high levels of "salts", the water soluble forms of minerals. Water dripping into the soil deposit more "salts" where they remain as the water is used or evaporates, concentrating, building up, frequently to toxic levels, until they are either flushed through with rains or heavier irrigation. Many of us here in the arid, drought-stricken areas have already witnessed the effects of increasingly saltier soil and water....."

great info, I'm off to read it all.