It could just be the result of the sun on a plant that hasn't been exposed to it for a while. Some roses are more susceptible to this than others, and it's something I've observed in my garden too. It's nothing to worry about and the plant will adjust. You can spritz some water on it with a hose and that should revive it.

Thanks very much, I was starting to think it was diseased. I'll try that idea of a lawn chair to see if it makes a difference. We did have a cool shady spring and now it is very hot and the sun has been beating down on it. Definitely in a full sun position with sun from sunup to sundown. I have Beverly, Savannah and Julia Child that are all doing fine and pushing out new foliage and buds, but maybe PJP, as you said, needs a little relief from the sun on cloudless days.

Is PJP smaller than the others? Is it any closer to any hardscape (walls, sidewalks, stepping stones, etc.)? Might there be a larger tree root under PJP which might be competing for water with it and not the others? It might be that it simply requires relief from the extremes. It might also be something increasing the heat or reducing the water to that particular plant.

Its roots might not be as well developed as the others so it can't use all the water it gets, or it just needs more water. What happens when you water it after it's been wilting? Is this a permanent condition or does it pass as the hottest sun passes? Spritzing and slight shading should help as suggested above.

Do you have unwelcome guests living in the soil, dining on the roots? If not then just hose the whole plant down during the late day.

No, I don't think PJP is smaller than the others. They were all planted at the same time. PJP was the first to bloom and it quickly pushed out new foliage and buds after it's first flush of blooms. It has buds on it now, some of which look close to opening. I can say that I was surprised that the flowers have outer petals that brown a little before the bloom is fully open even. I thought that was just a character trait of this particular rose. That's the only thing I've been disappointed about this rose.

It actually has more room and less competition from surrounding plants than the others. No tree root competition that I can imagine. We had 3 inches of rain the day before, so I can't imagine that it needs water. I looked at it after the sun went down and it was not looking wilted at that point. The plant looks healthy otherwise, so if there were insects on the roots, wouldn't that show in the condition of the foliage?

That's why I was asking if it's time dependent. Often times plants will do this during the middle of the day and recuperate later in the day. Why this one does it and others don't is anyone's guess. However, you could try just giving it some water and see if it perks up during the day.

Pick an open flower, hold it over a white piece of paper and tap it to see if you knock out any tiny insects on to the paper. If so, they are likely flower thrips and likely responsible for the browning edges of the petals. They generally prefer light colored blooms, though they can be found in almost all colors. When you smell a flower then have a tickle in your nose and possibly sneeze, it isn't "pollen". It's BUGS!

Hhm...I think I'd try shading it and would remove all of the flower buds-it might just be a little slower to establish than it's mates, and is struggling to cope with sun, trying to establish itself, and flower all at the same time.

I went out this morning and inspected it again. It wasn't wilting at this point, there's no sun on it yet. And there are a half a dozen buds on it, some just starting to open. The 'browning' I saw before, is back on those that are opened the most. And at closer inspection not just the outer petals of the blooms, but a couple more layers of the flower inside it seemed to be browning at the edges. Then I saw very tiny black bugs. Not a lot of them, maybe 3 on the worst looking flower bud and none on the others. Since I am an organic gardener, I tried to take the hose with the nozzle on stream and sprayed it close to the flower buds and tried to get the small black bugs and get rid of them. Then I pulled off the petals on the outside that were damaged and rinsed the buds affected a couple more times. Is the wilting related at all to the bud bugs?

I am going to be watering this morning and give it some more water. Later today I am going to put a lawn chair over it for awhile. I am going to leave the flower buds and keep an eye on them to make sure there are no more bugs.

I don't know whether to be glad the 'browning' is due to bugs or not. [g]

On my roses the bugs that turn things brown are called thrips and are super tiny. I wonder what bugs you have. Did you see any teensy things moving quickly inside the buds. For me there are usually quite a few as opposed to just a couple.

No, I didn't see any teensy things moving. Actually, rinsing off the buds with a stream of water, seems to have improved them. They are opening and looking better. And today is forecast cloudy weather and rain later, so that will work. I watered my whole bed by hand yesterday morning and we had some shade in the afternoon.