I've ended up with 4 leaves left, even after sweeping behind all trees. I know this was a game jam game, but it would be nice if the trees became transparent when the player goes behind them.
Sorry for the issues, I did not make a fix in this game after the jam. There's a lot of things I would change with the experience I have now, this game is actually unlisted on the website so you probably got here by an external link, thanks for that and for playing!