Where do you think those moths went?
Try heading towards the first large purple plant that you saw (the one that's always been closed).
Start heading back to where you got dropped off by the blue vine. But, as soon as you see the purple plant that's always been closed, go left on the path instead of right.
Oops - I need to get back up to the big tree. How do I do that?
Can you explain what I'm actually trying to do on this level?