Pontederia

Pickerel weeds are marginal aquatic plants, from across the Americas, with often lance-shaped leaves and blue flowers. We have two forms, all growing in our water garden ponds, one noticeably taller than the other. In the US Pickerel tends to refer to a couple of  freshwater fish species, whilst in the UK it normally relates to a young pike. It's also used to name a few East Anglian riverside pubs!