I got Frontier Twirl last season and it bloomed and bloomed. I don't spray either and it was very healthy. But it had major winter damage here (we got down to something like 4 degrees) I had assumed that since it was a Buck rose, it would sail through Winter but I was wrong. It is tiny now but trying to grow back. If it does that same thing next winter I am afraid it is out.

I don't spray either. I have had many Buck roses die over the winter. Some are definitely hardier than others. This winter Quietness was hardy to the tips. Earthsong dies to the ground and takes a while to come back. I was considering Frontier Twirl but if it has that much problem in zone 7, I don't think it will survive in zone 5a. Prairie Star died over the previous winter. On the other hand, Prairie Breeze is very hardy. Honeysweet dies to the ground but comes back to about 2 feet tall. Distant Drums and Silver Shadows come back but are very small.

I live in Zone 5 close by Peoria, IL. My experience with 'Earth Song' is that it is fairly tip hardy here if the winter temps don't fall below zero. I didn't have to do much pruning this spring compared to last spring when it got down to -22F for 3 days and I had to prune ES down to the ground. Even then, I find it regrows every quickly into a large shrub.

Earth Song is healthy here and a tremendous bloomer. It is one of my favorites. It is tip-hardy at 5 degrees, which is our usual winter low.

That surprises me. I would have thought both would have had hardiness similar to Quietness. In my area die back would vary significantly from year to year. Thanks for the input.

David

Hardiness in many cases indicates the rose will grow back if the canes are winter killed. It doesn't necessarily mean the rose is cane hardy. Many Bucks are not cane hardy in really cold climates.
Earth Song for me stayed green almost to the tips this past winter. Serendipity and Les Sjulin both died back to just a couple of inches

Besides Quietness,the only other Buck Rose I've had experience with is Mountain Music. It has cane dieback, but comes back faithfully every year. I do mulch all of my roses with about a foot of leaves. I killed off Silver Shadows right away -- but Quietness has survived a year with no mulch at all and another year of having to be moved late in the growing season.

Mountain Music is a continual bloomer -- the only drawback is she is a japanese beetle magnet. They fly right by other roses to devour her -- so I really can't recommend her.