Any ideas what causes this. Photo below.

It looks like the fungus Black Spot. One of the more common plagues of roses everywhere.

Yes, it's blackspot and very common. It can spread to other leaves, especially through rain or overhead watering, where water splashes from infected to uninfected leaves. The infected leaves will gradually turn yellow and fall off the plant. It can gradually defoliate a rose bush. Get a fungicide spray at your local garden center, Home Depot, Lowe's, or hardware store.

Thank you. I have been using Bayer fertilizer granules. It indicates control of black spot. I guess not. Thank you again.

@cdlvj130 ....

There are seventeen races of black spot in the world and five are found in the US.

It's highly likely any fungicide does not address them all ... but, you may find a fungicide spray that addresses the race or races in your garden. I think the sprays are more effective than using granules, but that is a personal theory. I have not seen studies comparing the two forms of delivery of fungicide.

Thank you so much. Does not help with the intense heat each day with absolutely hardly any rain near Austin. I have some spray and have applied. Thanks again.

Here I find that it actually gets too hot for blackspot, so it is mainly a spring and, sometimes, fall nuisance.

You are spot on, @Porkpal. Black spot spores are inactive once temps hit 85F.