Petalburg Woods is the main woods of Hoenn.
Head north to find the first trainer on the route.
North of Lyle is a Paralyz Heal. Grab it and move on. As you encounter a Devon Researcher, he asks you if you've seen a Shroomish. As you're talking, a Team Grunt (Team Magma if playing Ruby, and Team Aqua if playing Sapphire) appears and asks him to hand over some papers. The Researcher hides behind you, and you'll have to battle the Grunt.
After you beat the Grunt, he'll run to Rustboro. As a reward, the Researcher gives you a Great Ball. Keep moving to find another trainer.
North of James is an Ether, which restores move PP during battle. Head north back onto Route 104.
| Sapphire | Encounter Rate | Ruby | Encounter Rate | Emerald | Encounter Rate |
|---|---|---|---|---|---|