Where are you located, Jim? Mid summer can be tough for roses. Don't give up yet.

In new jersey summer has been very hot and have lots of rain

I think people in your area can pitch in and advise, now that they know where you are.

Sorry Jim, do you mind sharing what size pot are you using?

I do not know much at all about growing roses in pots, but in my experience you probably should use at least a 17 inch pot for an average rose. Even my drift roses struggle in a 30 inch pots during the height of the summer.

The pot is about 20” in diameter and about 16” deep it is a large pot that is in direct sun for most of the day have not checked if the soil drys out however

I need to water pots daily here in Summer.

Our climate is different, but rain does not water pots adequately where there is rain in my experience.

Pots need to be watered here daily also for the roses to be happy when the temps hit 90. Give it daily water and see if it improves.

@Jim Mac that direct sun and heat is literally cooking your rose's roots. Roses can withstand the heat and direct sun, but their roots can't. Sun shining directly on the pot heats up the soil ball and can actually cook the roots which grow out to the pot sides then circle the soil ball as they grow. That heat not only bakes out all of the soil moisture but also speeds up bacterial and fungal activity which digests the organic material in the soil mix faster. It can also incredibly speed up the break down and release of any time released fertilizers you may use. Increasing the heat in the root zone causes water stress on the rose. You can literally force a rose to both rust and mildew by water stressing it. If the roots were planted in the ground, they would remain a relatively constant temperature instead of experiencing the wide swings of cooler night temps to high extremes due to the hot air (like a convection oven) and direct sun (like a gas or electric burner on a pot or pan) on and surrounding the pot.

Ideally, if you can't plant the rose IN the ground, you should use an insulated pot such as a foam, wood or concrete which help reduce the amount of temperature transmitted through the pot sides into the soil ball and roots. You can also obtain a larger pot than the one the rose is planted in, place the planted pot inside it and either use thin Styrofoam or bubble wrap (preferably with as large "bubbles" as possible to maximize the air insulation between the pots) to insulate the root ball against temperature extremes.

Placing the pot ON a hard scape surface increases the heat in the air surrounding the plant very much like putting it inside a convection oven. To get a good idea of the effects of the sun shining on the hard scape, stand barefoot on that hard scape after the sun has been shining on it a while. Try it again a while after the sun has moved from shining directly on it to see how long it continues to radiate that increased heat. The combination of all of these factors literally cooks the potted rose sitting on the patio. That cooking inhibits the rose's immune system, forcing it to try to survive while suffering from fungal (and likely insect) attacks in its weakened state. It doesn't need chemical intervention, it needs heat reduction to the root ball and heat reduction to the air surrounding it to reduce it's water stress and literally being "baked".

You can also reduce the root heat stress by using the largest available pot you can find that's insulated (foam, wood, etc.) or obtaining the large pot and then lining the interior with multiple layers of either Styro Foam or bubble wrap to create the effects of an ice chest and reduce the heat transfer to the roots, then planting the rose inside the insulated container. Larger soil balls insulate significantly better than smaller ones. Of course you have to balance being able to move the plant to winter protect it and heat protection so whichever method of reducing the heat extremes to the roots works best for you to be able to handle the plant is what you should choose. It very likely doesn't matter what rose you select to grow there as those issues will remain if no changes are made. Some may be more diseased due to less genetic immunity to diseases. It's rather remarkable the plant is producing any flowers as flowering is ovulation in preparation to set seed (pregnancy) to perpetuate the species. Enduring those heat extremes could easily prevent it from flowering at all as it struggles to simply survive being cooked. I hope this helps provide you what you need to mitigate the temperature issues the plant is suffering. Good luck!

Kim is right. My plants in plastic pots placed into ceramic pots to avoid direct sun on the black pots are happier. In some of this heat putting the plants in partial or complete shade is the answer.

In Alaska, everything needed as much sun as possible, and here it can be the reverse.

survive. I'm going to completely revamp my thinking about how to pot in this climate and with these conditions.

Woops. First half of post gone into the ether. I wanted to say, Kim, with my pale sidewalks and beige walls, I'd never really made the connection between heat--not water!--and root health..

It's a miracle any of my pots survived.

I struggle to keep mine healthy also. Will make changes.