Heading out into the route, Shauna will catch up with you and tell you that the people you saw before were heading west, stopping you from heading north-west for now. Let's follow the path west then! You'll see a path leading off south. Feel free to head down it now.
In the next area, you'll be asked to look after a guy's berry fields. Feel free to do so and he'll show you how to use berries, as well as giving you Oran Berry x5, Pecha Berry x5 and the Sprinklotad for watering planted berries with. From now on whenever you see soil that you an plant berries in, feel free to place one in.
After watering and waiting for a while (real time); the berries will grow into plants that can be harvested to get even more berries. Pretty much the same thing that you could do in Gen III. You can also destroy three berries to make some Mulch by interacting with one of the green composters. This can be used to fertilize soil to make berries grow better.
If you want more information on the whole process, visit the farm in the north-east corner and talk with them. Once you're done, head to the south-west corner of the area to find a Miracle Seed . Then head back out of the area.
Tip #012: Berry Power
Berries can be held by Pokemon for various special effects. Depending on the situation, the Pokemon will automatically eat the berry in battle to gain the effect. For example, if a Pokemon holds onto the Chesto Berry , they will instantly recover from sleep once!
Now that you're back on the path, head west. You'll eventually reach the two guys from the castle before, standing by a freaking Snorlax ! OMG YES! You'll be told you need to find the Poke Flute, which can be found in Parfum Palace located past Route 6 - Palais Lane .
I guess that's where we'll be going next. First though; head along the thin path north, alongside the river below. At the end of the path you'll find a Heal Ball . Now backtrack to the crossroads where you could go either west or north-west, the place where Shauna forced you to west. Now it's time to head north-west into Route 6!