Posted: Yesterday at 17:03
Ordinarily when leaves on a very hardy fast growing shrub like a red ribub photinia go brown then it's due to either: drought or waterlogging.
Brown leaf tips tend to indicate drought at spring / summer time and that it's affected the young new growth. Brown spots or patches in the middle of the leaf usually means it's been waterlogged.
Yours looks like it's had a bit of both. Anything that's contained in a pot is going to be susceptible to that. In the case of this VERY easy large and fast growing shrub as dovefromabove said, it won't want to be in a pot.
They can also get fire blight which makes the leaves go brown but from your description I'm not thinking it's that.