Water mint, hierbabuena de agua

It is a herbaceous rhizomatous perennial plant growing to 90 centimetres tall. The stems are square in cross section, green or purple, and variably hairy to almost hairless. The rhizomes are wide-spreading, fleshy, and bear fibrous roots. The leaves are ovate to ovate-lanceolate, 2 to 6 centimetres long and 1 to 4 centimetres broad, green (sometimes purplish), opposite, toothed, and vary from hairy to nearly hairless. The flowers are tiny, densely crowded, purple, tubular, pinkish to lilac in colour; flowering is from mid to late summer. Water Mint is pollinated by insects, and also spreads by underground rhizomes, like other species of mint. All parts of the plant have a distinctly minty smell