Lobelia fulgens Queen Victoria (Red leaved cardinal flower, Scarlet lobelia) has leaves which are actually purple, not red, but there’s no arguing that the flowers are red!
Lobelia siphilitica (Blue cardinal flower) has light green leaves forming a tight rosette in winter then produces erect stems with blue tubular flowers in late summer.
Luronium natans (previously Alisma natans), Floating water plantain, is a rare native plant of shallow water and wet swampy areas, producing oval green floating leaves and small white three petalled flowers.