So i today i got the Towering wisdom achievement in Plants Vs Zombies, that requires you to grow  the tree of wisdom to 100ft which is a pretty tall order because it requires large amount of money. If you were play the game normally it would take forever but there's is a small exploit that you can do involving the mini game Last Stand, here's a video that show you how to do that. Also by now you should have fully grown plants in your zen garden that you can sell for 8000 a piece,that should help a little.
Hopefully what i wrote helps someone achieve the Towering wisdom achievement because that one was real hard one, be prepared to spend hours grinding for money.