Can you figure out the meaning of this poem?

I think it's more of a don't let time p you by kinda message. At the beginning it's saying that flowers and gr and birds don't let the fact that fall is just around the corner get them down. They live for the moment and cherish what nature gave them. And you should too! Maybe I've missed something, but I think that's what it's about. Who wrote this? It's a beautiful poem