I've upgraded everything to the max and I'm making a lot more money than I need to keep everything going - wish it was that easy in the real world, I'd have a store by my own then. By now I've sorted out all plants worth less than 70$ and I've found five out of six magical plants (the goal of the game being to find all six). Here they are:
Actually, I'm not really in a hurry when it comes to finding the last plant. As the game runs nicely while I'm writing or doing other stuff, it didn't get too boring.
Growing digital plants is quite relaxing and doesn't get anything dirty in the real world, either.