Go down the path. If you have one Grass-Type Pokémon in your party, a girl will give you TM19 (Giga Drain). Grab the Berries here: Pecha, Sitrus, and Rawst, and follow the path to some more Leppa Berries. Then, hop off the ledge to the left to collect an Elixir.
Cooltrainer Wendy Mawile: Level 31 Roselia: Level 31 Pelipper: Level 31
Psychic Jacki Kadabra: Level 31 Lunatone: Level 31
Twins Miu & Yuki (Simultaneous)
Beautifly: Level 27
Dustox: Level 27
As you move to the left, on the low path, collect the Ultra Ball near the fence. If taking the high path, be sure to grab the Calcium. Either way you go, you'll end up at the Berry Master's House. Near the house is Aroma Lady Violet.
Aroma Lady Violet Shroomish: Level 25 Breloom: Level 25 Gloom: Level 25