You have a nifty idea here. I got some ways in before I felt like I was just dancing around the game board, but there might be more to it than that. Plus, it's difficult for me to control two characters so quickly, but that means challenge.
The visuals are cute, but need some sprucing up (like some color) outside the plant. And lastly, sound. Cute, soothing tropical music might be nice, allegro for when your plant is getting low on health, and maybe some bleeps and bloops for sound effects.