Very impressive idea, have not seen anything like that! I loved it. And the art style with chosen music made the whole experience very enjoyable. I did not manage to solve all the levels, but I really liked the unique approach to the theme, really well done!
The one thing that might be worth checking out if you decide to continue working on this game in the future, is that water stops filling up if you make a big hole. I think I encountered it on level three when I needed to use one plant to make a pool of water so the other plant would start getting some water. Even if the water was constantly running pool stopped filling after some time. But it was not something too concerning, since I just replayed that level by making a smaller pool.
I liked the fast-forward feature too!
Overall, I enjoyed it. It was actually a unique and nice experience!