Do you have close up photos of the bloom? Especially in different stages.

I can tell you that those stones as mulch are deadly to roses. They hold in too much heat, and fry the roots. A plant-based mulch is better, compost or shreded leaves or wood chips. If the blooms aren't holding, look at how much water they are receiving.

I agree with Diane NJ -- too much heat from the rock mulch is not helping the roots.

The rocks and the brick wall may also reflect heat that can dry out the blooms and leaves, although the foliage looks okay in your photo.

Make sure the bushes are watered deeply, so that all of the roots are soaked. After you think you've watered enough, dig a little hole next to them until you hit dry dirt to see how far down the water actually went.

Even though we'd need to see a fresh bloom to attempt an ID, all roses have similar cultural requirements.

I'll put a link below to articles from a southern California rose gardening club. You'll find good starter advice in the section on Soil, Mulching & Fertilizing, and in General Rose Care:

Here is a link that might be useful: rose gardening articles from SCVRS