I absolutely love this - a good deal of strategy involved despite feeling fairly frantic. The last level largely involved spamming trees around the central building to stop it swamping the land quite so much, but even that took a bit of thought up-front (and it's possible that I would have been able to take the boss down more efficiently if I'd been quicker to surround it with greenery to begin with). Plus, it's a suitably hefty obstacle for the final encounter.
The main thing I'd like to see is more levels - or (though I realise it's probably a huge ask) a level editor. It would be great to have a few where those bee-attracting plants were crucial to success - maybe a few little islands that have to be seeded with grass manually before you can plant there.