When does Bellsprout evolve?

At lv. 22, but you have to use a leaf stone to evolve it into victreebell which can be found at the celadon dept. store. You can get them for 2100 coins.









Hope I helped!
Bellsprout evolves into weepinbell at level 21. Weepinbell evolves into victreebell with a leaf stone.

Hope I helped!