Question
I live in Eastern Utah, and it has been very warm as in a lot of the US. We are in a dry desert-like area.  My rose bushes, three of them, seem to be loosing leaves.  Also the leaves on two are yellowish or pale green as if there might be an iron problem.  I have a spray on iron that seemed to help last year, but isn't this year.  A new bush I bought this year has leaves that almost seem sunburned, they are bright yellow in spots, but don't have any black spots.  More like brown dried areas. They get watered every other day with the sprinkling system.  I appreciate your help.  

Answer
What you are describing is a rose under stress. Roses save themselves by first not flowering or by making frail looking blooms, the next is that the leaves go yellow and drop off and finally the rose canes will start to die back. Under high heat roses start to conserve the use of water. To do this they must first drop their leaves and go dormant. Also, again when the temperatures are high, droplets of water will magnify the sun on the leaves and actually burn them. Your rose is just reacting to the stress of too high heat. Some roses actually prefer a cool type of climate and so re-act far more seriously then a rose that likes the heat.I am in the PNW and we are getting high temperatures for a long time. There are many leaves as you describe in my garden and I am getting to know those roses that don't like the heat. Your rose will come back normally when the temperatures return lower. Hope this helps.