Pretty in Pink

Carroll Creek
After the rain stopped today I spied a tall flower growing right on the bank. A closer look revealed a weed-like plant about 3' high with an interesting flower group that a couple of bees were working over. There is also a little vine that has grown up the stalk and has the lighter leaves as compared with the darker and narrower serrated leaves of its host I attempted identify this plant but could not find in the Internet. Anyway the bee was "pretty in pink"