Red drift rose
Can drift roses bloom in less than 4 hours of sun? Have an area that gets full sun about 2 hours of afternoon sun.
I checked several references and they all say full sun - 6+ hours daily. Less than that and your rose will not produce as many blooms. Blooming takes a lot of plant energy; fertilizer doesn't replace the energy gained from photosynthesis. How much less, I don't know. Have you considered growing it in a pot placed in full sun?