Originally Posted by
Drip
It does slow down a lot once you complete the campaign. However, the daily reward changes once in a while, and I've had several weeks where every day gave a flower gem.
Maximizing your affection with the girls also gives a flowergem for *each* girl, so as long as you get new girls, you'll get flowergems.
There's also a very small chance to get flowergems from gathering. I've had it happen twice so far, so the chance is really marginal, like... 0.01% I think.. :-/
And, finally: not all girls come from the gachas, some girls come from the events. There's always another event, so there's always a new girl (with a flowergem for maximizing her affection!)