A lady down the road gave me this plant for my pond a few years ago. She took it from her pond. She said someone gave it to her and she did not know what it was.The leaves and flowers are small. http://images.yuku.com/image/pjpeg/21a16b455d3b70dad7c1390861ccd2881dc62d0e.pjpg
I think you have Cicuta maculata there. AKA water hemlock. Bloom is actually white and not the faint blue from the pic? Poisonous and generally avoided for cultivation by anyone unless you're going for a "Rappacini's Daughter" effect.
So you waited a few years to find out what it is? You have been procrastinating! Seen rather often in ditches and other quiet wet places up here, too.