You go and level it to Level 21, where it evolves to Weepinbell.
bellsprout and what they evolve into
Bellsprout has to be found wild, in leafgreen, you need to trade from Leafgreen for Pokemon.
Bellsprout is exclusive to Pokemon LeafGreen, so unless you trade, you will have to settle for Oddish.
You can't catch Bellsprout in Sapphire. You have to trade it from LeafGreen.
Bellsprout is not available in firered it's only available in leafgreen.
Bellsprout is exclusive to Pokemon LeafGreen, so unless you trade, you will just have to settle for Oddish.
Bellsprout evolves into a Weepinbell at level 21 in Pokemon Crystal.
http://www.dltk-kids.com/pokEmon/adoptions/bellsprout-p.htm (two evolutions)
Bellsprout > lvl 21 > Weepinbell > leaf stone> Victreebel
In Pokemon Sapphire, Ruby, Emerald, FireRed, and LeafGreen, Bellsprout will learn Sweet Scent at level 30 if you do not evolve it. In Pokemon Diamond, Pearl, and Platinum, it'll learn Sweet Scent at level 29.
Bellsprout evolves into Weepinbel at level 21.
Bellsprout evolves into Weepinbell at level 21, which evolves into Victreebel when a Leaf Stone is used on it.