Water Mint

Sint Jansklooster, Holland (Aug, 2013).
It is a herbaceous rhizomatous perennial plant growing to 90 centimetres (35 in) tall. The flowers of the watermint are tiny, densely crowded, purple, tubular, pinkish to lilac in colour; flowering is from mid to late summer. All parts of the plant have a distinctly minty smell.
Habitat: Water Mint occurs in the shallow margins and channels of streams, rivers, pools, dikes, ditches, canals, wet meadows, marshes and fens.