How many hours of sun does hansa and Bonica rose need?
You can grow roses in less than optimal full sun. Minimum 6 hours is the general recommendation. You will notice a difference in performance in less than optimal conditions such as less repeat and bloom but you can still enjoy roses. You may just get a good bloom in June and not so much going forward.
Mine are partially shaded by the pear tree and they did better last summer when I trimmed it back.
My bonica and hansa are doing well with 5 hours of midday sun, this year will be their 3rd year in the ground.