How to Find Combee in Pokemon

Go to Floaroma Meadow in the game. There will be a man there selling honey. Buy some honey from him.

Locate a "honey tree." These are distinctive golden-yellow trees scattered around the map. Conveniently, there is one in Floaroma Meadow where you will have purchased the honey.

When you have located the Honey Tree, spread the honey from your inventory onto it. Continue playing the game as you normally would until 12 or so hours of in-game time has passed.

Return to the tree that you covered in honey. If you've allowed enough in-game time to pass, the tree will be shaking, indicating the presence of a Pokémon.

When you see the tree shaking, don't interact with it right away. Instead, save your game!

Interact with the tree. If you're lucky, you will be confronted by Combee at this point. If so, disregard the next step.

If you're confronted by one of the other possible Pokémon, such as Burmy, restart your game. Since you've saved your game, you'll find yourself in Floaroma Meadow near the shaking tree. Interact with it for another chance to encounter Combee. Repeat as many times as necessary.