Water Plants
Ceratophyllum demersum
Hornwort
Whorls of fine dark-green foliage form soft underwater cover for small pond creatures. This rootless aquatic plant floats beneath the surface and can grow into a dense mass, making occasional thinning useful in small ponds.
At a glance
- Sun
- Sun to shade
- Pond placement
- Submerged in still or slow-moving freshwater.
- Water depth
- Water up to about 5 ft. deep; no soil needed.
- Winter care
- Dormant buds can rest in bottom mud and regrow in spring.
- Mature size
- About 3¼–5 ft. (RHS range) wide
- Water
- Fully submerged in still or slow-moving freshwater
Depth here is the total water column for submerged stems, not water above soil.
Sizes & prices
- bundle$6.99
Catalog updated September 8, 2026. This is not a live stock count; please call to confirm availability and price.
Ask about this plantSelect a section to expand.
Resistance & tolerances
- Wet soil
- Aquatic; keep submerged.
Water garden care
- Type
- Submerged oxygenator.
- Planting method
- Allow rootless stems to float below the surface.
- Pond benefit
- Oxygenating growth and underwater cover for pond wildlife.
- Spread
- Remove excess growth; never discard into waterways.
- Size & placement
- Submerged, mat-forming growth; the reference describes growth to about 5 ft. water depth. This is not a 5 ft. upright plant above the pond.
Sources & photo credits
Photo: Bernd Haynold · CC BY-SA 3.0
Reviewed September 27, 2026. Growing conditions vary by location.