First. Forget whatever you might have read anywhere else, any other time, no matter who the authority, about rose care before you moved to the Mojave Desert.
Second. Run, do not walk, to the nearest source for the Sunset
Western Garden Book or any of its little brethren, esp. one on roses. Sunset understands western climates as no other publisher in the English language does. Learn what your Sunset climate zone is, then see what Sunset recommends for rose care in said climate zone.
Third. Whatever Sunset says to do, do it. Your roses will be happier, and you will therefore be happier.
Sunset saved my...ah..."behind"

when I moved to California from Georgia after college. I came from a four-season, "normal" place to the weather-wise very weird San Francisco Bay Area, where it
never rains in the summer,
only rains in the winter, and planting of trees
must occur in October.

Sunset to the rescue.
I hope you can bring some of your roses back to good health!
Cynthia H.
Sunset Zone 17, USDA Zone 9