Channels
When you log into the game by entering your username and password, you also have the choice of what channel you want to play in. To hunt for leaves, it is best to pick a channel that does not have many other players in it. This means you can hunt for the leaves at your own pace without worrying about other players clearing out the areas and taking all of the leaves. A small bar underneath the channel number indicates how full it is.
Victoria Island
The best region to hunt for leaves is on Victoria Island. This is because it is the only region in "MapleStory" where the monster that drops leaves can be found in abundance. Victoria Island is very beginner-friendly, as the monsters are not as powerful as they are in some of the other regions. The Island is also the starting point for some of the character classes, which makes it even easier to hunt for leaves.
Perion
The best place to hunt for leaves is in the Perion area where the enemies that carry the leaves roam. The maps called Dusty Wind hill and Mini Rocky road are found just north of Perion, and have many Dark Stump enemies. You can easily reach Perion by traveling from Six Path Crossway in the middle of Victoria Island. Magician and Warrior class players can find these monsters in their training centers as well, but since these areas are off-limits to other classes, it's not the best place to hunt for leaves.
Dark Stump
The Dark Stump is the only enemy in the game that drops the leaves. Its appearance is that of a tree stump, which moves around on four roots, and it has a single eye in the middle of its body. It does not have any visible leaves, but can randomly drop one when hunted down and killed. You can then pick these leaves up and add them to your character inventory, but you can only keep a maximum of 200 at a time.