Mine is planted in an area with morning sun, afternoon shade. It's still blooming.

I have two planted in an area that gets perhaps one to two hours of afternoon sun. She is still blooming. The plants are not as large and do not bloom as profusely as those in full sun, so... I will just have to plant a few more.

I have my 8 Rozannes planted in a bed that used to be full sun, but when I thought about your question, it occured to me that mine are actually planted in partial shade. They are underplanting an area with 3 Knockout roses, a Viburnum which has recently, when I wasn't looking, become taller than me & about 4 ft wide on the South side, 3 Virginia Sweetspire shrubs (3-4 ft tall and wide) on the East, 2 very large grasses to the North, blocking a lot of light, and various other (18 - 30 inch)perennials and some low evergreens to the West. So they are getting mostly afternoon sun, except I forgot there is a good sized (higher than the fence) Weigela to the SW side and a Smokebush which I sometimes hard prune and sometimes not to NW side, so even some of that sun is blocked. Makes you wonder, when you think about how much stuff if crammed in there, that the Roses are blooming - but both Knockouts and Rozannes bloomed their heads off this summer. My Rozannes are not 1st year plants so I did do some considerable amount of chopping/lopping of stray Rozanne stems as necessary to keep them in bounds.