Ceratophyllum demersum (Hornwort / Hoornblad - pond)

Ceratophyllum demersum is one of the most effective submerged oxygenating plants for ponds, forming dense bushy masses of dark green, bristly whorled foliage that oxygenates the water column, absorbs excess nutrients, and provides spawning habitat for fish and amphibians. Completely rootless, it floats freely or can be weighted to the pond bottom. A staple oxygenating plant in Belgian and Dutch pond shops.

No planting required — simply place bunches in the pond or weight them gently to keep them submerged. Tolerates full sun to partial shade and a wide temperature range including near-freezing in winter. Trim back regularly in summer to prevent overgrowth. Remove excess biomass in autumn to prevent decomposition affecting water quality.