The one I got a number of years ago is quite spectacular for a once-blooming rose. It's about 7 feet high and 7 feet wide now, and when it blooms in late May, it has hundreds of flowers. The bloom time lasts a few weeks because it has so many flowers.
I'll quibble with "thornless," because I started lopping off a few dead canes that were underneath many live canes in the Spring of 2020, and should have gone to get my gloves. I was in my own little groove, though. When I was done, there were a lot of thorns in my hands.
The flowers are in clusters, with the top bud opening first. The buds are beautiful, opening to an informal flower, as shown above. The flowers have a pleasant fragrance. The plant is extremely hardy.
If you have room for this very vigorous rose, you'll be treated to quite a show in late Spring.
Vigorous, very hardy, very fragrance, super healthy, and long lasting blooming. The spring flush is fabulous. What can we ask for to a rose? If you can grow only one once-blooming rose, this is it!