Ceratophyllum is a very good oxygenator & can grow to great depths so is ideal to put in lakes & ponds. It is a free floating plant but weighting helps secure the plant in the required location. Hornwort has foliage that resemble small horns from the Greek Ceratos (horn). Flowers May-July. Height 15cm. Miniumum depth 30cm; maximum depth 200cm. Native. Growth rate medium.