Propagating Ceratophyllum echinatum 'Red Foxtail'

How to propagate spiny hornwort 'Red Foxtail' by stem fragmentation: this rootless floating oxygenator regrows from any cutting, with no substrate planting required.

Overview

Ceratophyllum echinatum, the spiny hornwort, is a freely branching submerged perennial whose stems grow to several metres. Within the genus Ceratophyllum roots are completely absent — they are missing even at the embryonic stage — so the plant has no true root system and is not anchored by roots in the substrate.

The plant grows fully submerged and usually floats freely near the surface, though some hornworts develop modified rootlike leaves that allow loose anchoring to a pond bottom. Its much-branched whorled leaves make it an effective oxygenator. The 'Red Foxtail' form is a finer, reddish-tinted selection of this North American species.

Propagation Method

Hornwort is propagated vegetatively by simple fragmentation. Because the stems branch freely and lack roots, almost any detached piece will continue to grow into an independent plant — there is no rhizome to divide and no need to plant cuttings into substrate.

Step-by-Step

Choose a healthy, densely leaved stem section that shows the reddish flush.
Pinch or cut off a fragment of any length — even a short tip will regrow.
Drop the fragment into the water column; it will float or drift to a resting spot.
If you want it to stay in place, tuck the base loosely between hardscape or substrate rather than burying roots.
Within days the fragment resumes growth and develops new side branches.

Conditions for Healthy Growth

This species favours clean water more than common hornwort. Provide medium light; CO2 is not required. It tolerates a temperate range, roughly 16–26 °C, with a near-neutral to slightly acidic pH (about 6–7.5) and soft to moderately hard water. As a low-demand plant it draws nutrients directly from the water column.

Lighting: medium, no CO2 needed
Temperature: 16–26 °C
pH: 6.0–7.5
GH: soft to moderate

Maintenance

Trim about every two weeks to keep the stems tidy and to prevent shading of lower plants. Collect loose fragments after trimming, since each one can root-free continue growing. In autumn hornworts may form turions — thick buds that sink and overwinter — then regrow in spring; these can also be left to restart growth.

Common Challenges

Because the plant is rootless and brittle, it sheds leaf segments under stress or rough handling, which can litter the tank. It also demands cleaner conditions than typical hornwort, so in dirty water or under poor light it may drop leaves and lose its reddish colour. Maintain good water quality and steady light to keep growth dense.