First off, welcome! Second, where do you live? What zone at least? There's no way to tell if it's too late to plant without knowing where you are.

As for what to plant, plant what you like! If you don't like KOs then don't plant them. Not knowing where you are I can't say how well Pink Peace will do for you but it is a very pretty rose. And yes, Hybrid Teas, like Pink Peace, will grow wonderfully in pots! Realistically, you can grow any type of rose, even climbers, in a pot if it's the right size and big enough.

Half barrels are a good size but what are those half barrels made of? Wood is not a good choice for potting roses because they rot and will eventually self destruct. I never recommend ceramics of any kind, even in warm zones where they won't crack, because they are TOO HEAVY by the time you put wet soil and a full grown rose in them. I know you think you won't ever have to move them once you plant them but I'll guarantee you will have to at some point in time! I have 60 some roses in pots and I always use plastic or those foam/resin type pots. They're lighter, easier to drill drainage holes in and last for many seasons. Even in my very cold winters. Very good drainage is the most essential thing potted roses need. So put extra holes in what ever pots you choose. Never use garden or top soil of any kind in pots. Always find a good quality, lighter weight POTTING soil.

OK, I won't bombard you with more right now. Just get your roses, pots and soil ready to go before you do anything else. But don't hesitate to ask more questions!

No, I don't think it's too late to plant any type of rose in containers. They'll be going into the garage and be protected. I plant mine in late May - but I would plant right up to frost, as long as they overwinter somewhere warm enough. All of my roses are hybrid teas, and, like Seil says, those foam/resin type pots are awesome with extra holes drilled in.
Have fun!!
Carol

Thank you so much! This was REALLY helpful! My barrel is made of wood so I'm definitely going to be potting my roses in something else. I'm in zone 5b, moving to a 6a in about a month, though. Miracle Gro makes a potting soil specifically for roses. I was either going to use that or the moisture control mix. I don't know much about potting soil-- Miracle Gro is the only brand I know!

Never mind, I just read that the rose formula was for in-ground roses! Moisture control it is!

It doesn't matter what brand as long as it's a good light potting mix that will drain well. I've used some with water crystals and others with fertilizers and some just plain potting soil. They all work as long as they drain well. I don't usually get the ones with fertilizer because I prefer to control what kind and how much of that they get but if that's what you find it will work. I've used many different brands. Miracle Grow is good but there are good ones out there that are cheaper.

I know I've stressed a lot about drainage but that's very important. Roses hate to sit with their roots in water. That being said, potted roses will need to be watered more often than roses in the ground. Pots dry out quicker. So it's kind of a catch 22. You don't want the roots to be soggy but you need to make sure they don't dry out either. You have to find the balance that works for you, in your climate and with the roses you purchase.

There are smaller varieties of roses also, in case the growth size in containers was something that you were concerned about, even though containers do help to control the overall size.

This year, I added miniature roses to my plants-in-containers, and I also saw something at Lowes or HD described as ground-cover roses. They seem to be very low-growing but still put out a great look of roses blooming.

And as for what others said -- I agree, grow what you want to grow! The pot size and your pruning will help keep it in check.