I agree with Suzanne. When I started my rose life, I lived in a condo and had to grow all of my roses in containers. The roses were healthy and productive and I thought they were doing quite well.
One of the roses I was growing was 'Timeless'. I loved that rose. One day, while working on a rescue project on the Naval base that was closed in San Diego, I saw a red rose that was stunning way across the park. I had to go and look at it. The rose was 'Timeless'. It was larger and fuller and looked like a completely different rose than the plant I was growing. That was my first hint that not all roses will reach their potential in containers.
Over the years, I've found this to be true for even some smaller roses. 'The rose 'Kim Rupert' always looked like a dawg when I was growing it in a large container, but I planted it in the ground because it was named after my rose mentor. That rose, even tho' it is smaller than most HTs, just took off and is now a beautiful plant. The rose has a spreading habit and when I gave it plenty of room to grow roots, it became a stunning rose.
I now grow only one rose in a container, but it's roots have pushed through the bottom of the pot and are now growing in the ground. It was a pretty rose prior to that, but now it is larger and far more prolific in bloom. I've left it in the container because I would have to butcher it to get it out of the container and replant it. Since the root mass is in the ground, I've decided to leave it alone.
Here's a photo of 'Green Ice'. (An own root plant.) It's been in it's container for 10 years without the soil being changed because the roots are in the ground below the container:
This is my budded 'Firefigher' which is now in it's second season in the ground:
My personal theory is that constricting the roots to fit in a container will impact the rose. You can grow healthy roses in containers, but when you site them where they can develop their roots, you get a better plant.