Acorus calamus (Sweet Flag) is an interesting perennial and one that is perfect for the bog garden.  Its bright green, sword-like leaves grow from three to five feet tall in my pond, but I have seen Sweet Flag reach over six feet.  The scented leaves and rhizomes of Sweet Flag have been used for thousands of years for just about everything:  perfume making; wine making, particularly for absinthe; strewing on cathedral floors; medicinally, as a tonic and to cure digestive ailments, to name just two; and, allegedly, as a hallucinogen.  It is believed that early Native Americans made a tea from the roots of Sweet Flag to ward off sore throats; they used the dried roots as a cure for runny noses; and they made a paste from the rhizomes for war paint.  As for me, I just use Acorus calamus, or Sweet Flag, in my water garden because it makes such a lovely statement and a scented one, as well, and that's quite enough for me.  Sun.  Zones 2-9.  Bare Root.