Question

Can you plant berries in B/W?

Answer 1

The answer is simply NO. That's all!

Comments

...well that sucks.

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You can plant berries but not in-game, only in Dream World. You need wifi for that.

Answer 2

In the games, the answer is sadly no. But that doesn't mean you can't plant berries! Berries can be planted in the Dream World and then sent to your Black/White. There is also a absurd amount of berries that can be found in the Dream World, so you don't even need to plant them.
Source: http://bulbapedia.bulbagarden.net/wiki/Dream_World#Garden