...in fact it seems that it would seem to even discourage interacting with your own beasties by feeding them if you have to grow berries first.
You don't need to grow berries to interact, instead you simply "Pet" the Pokémon to interact with it as normal except you don't need to click one of five berries to do so, just the pet button.
Berries are a new feature entirely, a consumable that - similar to cookies - would simply give a boost in EXP from the sounds of it. You interact with Pokémon the same as before, it's just been changed to petting instead of feeding a berry to interact!
