Sweet Flag is a perennial herb, semi aquatic, marshy plant with a creeping and much branched, aromatic rhizome. The rhizome is cylindrical about 19-25 mm in diameter and 10 cm long. It is light brown outside, white and spongy inside. The leaves are thick, erect and sword shape, when bruised emits strong scent. Sweet flag produces small yellow flowers on a spike. Plants rarely flower or set seed.
Sweet flag is a native to most Northern latitude countries around the world, widely dispersed around the USA. It is found wild or cultivated in India and Sri Lanka up to 1800 meters.
Sweet flag thrives best in marshy and moist places under variable climates.
The plant is grown in clayey loams and light alluvial soils of the riverbanks.