Helonias bullata

This is Helonias bullata, sometimes called swamp pink. It's native to Maryland, and it takes well to local conditions. It's been here in the garden for many years in one of the bog trays. It does not bloom unless I feed it occasionally. 

In some circles this is regarded as a bit of a trophy plant, but I've got to say that the first time I saw one in bloom in my garden it reminded me of some sort of bistort or clover.