purity forest
you can't.its impossible.EDIT: Wrong. You can find a leaf stone as a random prize in paradise or in the DLC dungeon "Skill Treasury"
you have to find a dungeon kecleon shop
Maybe you get it from a kecleon store not in treasure town but when adventuring
Buy it in Mystifying Forest in the Kecleon Markets for 1000 Poke Dollars
The fastest way is to earn points on the Pokemon-a-thon and buy a Leaf Stone there for 2500 points. The Leaf Stone is available at Thursdays I think. You can also get a leaf stone from Bill's Grandpa if you show him an oddish, he is just above Cerulean city. and you can find a leaf stone in viridian forest.
BY ****ING YOUR DS
You can find them in the underground.
you can find one under ground
to find a leaf stone is to find a nuzleaf and go into the cave of origin if you don't want to waste your time go to the forest near the rustboro flower shop and theres a pokeball in the middle of the garden that's a leaf stone.
it depends on what kind of game you have if you have mystery dungeon then you can catch one
u go to evolve place and give leaf stone
you have to get a leaf stone which you can find on the down, right side of the bridge after you pass the weather institute then evolve your lombre. you can also get a leaf stone by getting a green shard and trading it for a leaf stone.