It looks a little hungry to me. Are you feeding it regularly?

Could it be suffering from rust/blackspot, did you give it a good feed at the start of the season, and have you kept it watered well in the dry spell we had, now the first flush has finished, then you can give a second feed to encourage more flowers for thje remainder of the season, however never feed to late in the season, new growth wont have time to toughen up before the frosts, try giving it a good mulch in the future to keep in the moisture.

Good morning everyone. I gave it its second application of 50 grams of powdered rose feed at the beginning of June. (The first feed was in April). Plenty of soakings with the hose also, so cannot have been too dry at any time. I can't think what I have been doing wrong, yet the prceious plant seems to be going wrong.

Well, first I would check for moles/voles/grubs at the base of the plant. If it were me, I would be putting on that much food every month, but that may just be because I am used to having to water the roses twice a week in my climate. Other possibilities are borers in the canes, a change in grade around the base of the bush, nearby digging, or even more severe blackspot than is showing on the remaining leaves. Otherwise, I would just be guessing.

Moles, voles? If there were I'd have seen the beggars. I do not know of any rose grubs here in England. Of all the magazine articles published in this contry on roses we so little read of them. I should think think things are rather t=different in your part of the world, Arizona. My blackspot is mild only. Gardening somewhere so arid must be a real challenge. You must have to irrigate so much.

Oh yes! Roses do well here, but you need to buy stock in the water company! 30-40 gallons, twice a week in summer, or you can kiss the bushes goodbye!