I've let the purple cone flower self seed in this garden as they are a favourite nectar source too.
A saw a curious thing one afternoon though, and that was one monarch being territorial and chasing all other butterflies away from the butterfly bushes. It kept sailing round and round and even tried to intimidate me to move along.
I also grow several varieties of milkweed which is a larval plant for the beautiful monarchs.
I'm linking with Claudia at Dipity Road for Finding Beauty.