Pokémon Platinum / Gym 2 · Grass-type Gym Leader

Gardenia

Gym 2 · Grass-type Gym Leader · Eterna City

Gardenia leads Eterna’s Grass-type Gym. Her enthusiasm for plants and Grass Pokémon shapes the Gym’s garden setting.

Story: Her badge enables field use of Cut, which helps open the route into Eterna’s Galactic building.
In the game: First Gym battle in Platinum: Turtwig Lv. 20; Cherrim Lv. 20; Roserade Lv. 22. Fire and Flying attacks help. Roserade is fast and can punish a weakened team, so heal before facing it.
Gym puzzle: Defeat the trainers around the giant floral clock to rotate its hands and open the path.
Rewards: Win the Forest Badge and TM86 Grass Knot. The badge allows Cut outside battle once you have the HM. These are the first Gym teams, not the later Battleground rematches.

Story spoilers.

Pokémon Platinum · Nintendo DS · 2008 · Original Nintendo DS release; not Brilliant Diamond or Shining Pearl. · Picture: Original Nintendo DS-era Sinnoh Gym Leader sprite.