Hornwort (Ceratophyllum Demersum)

Hornwort | Ceratophyllum demersum

One of the Best Oxygenating Pond Plants for Clear Water and Healthy Wildlife Ponds

A Free Floating Native Oxygenator That Helps Reduce Algae While Providing Excellent Shelter for Pond Life

Hornwort (Ceratophyllum demersum) is one of the most popular and effective oxygenating pond plants available. This free floating native aquatic plant grows entirely beneath the water surface, forming dense feathery mats that help maintain clear, healthy pond water while creating valuable habitat for fish, amphibians and aquatic insects.

Unlike many pond plants, Hornwort does not require planting baskets, aquatic soil or special positioning. Simply place it into the pond and it will naturally float or sink to the most suitable depth. This makes it one of the easiest oxygenating plants to establish and maintain.

Hornwort is highly valued for its ability to improve water quality. During daylight hours it absorbs excess nutrients from the water and releases oxygen through photosynthesis. By competing for nutrients that would otherwise feed algae and blanketweed, Hornwort can help reduce unwanted algae growth and support a healthier pond ecosystem.

Its soft, feathery foliage creates excellent underwater cover for fish, tadpoles, newts and countless aquatic insects. It is particularly valuable in wildlife ponds, where amphibians use the dense foliage for protection from predators and as shelter during breeding seasons. Young fish and fry also benefit from the safe refuge provided by the plant’s bushy growth.

As a UK native species, Hornwort is well suited to British ponds and remains hardy throughout the year. It thrives in still or slow moving water and can grow successfully at depths ranging from around 30cm to 150cm. It performs best in ponds that receive a mixture of sunlight and shade but is adaptable to a wide range of conditions.

Hornwort is particularly useful in new ponds where it helps establish biological balance and improve water clarity. It also works exceptionally well alongside waterlilies, marginal pond plants and other oxygenating species to create a balanced aquatic environment.

Each pack is supplied loose rather than bunched, as Hornwort is naturally free floating. One pack provides approximately 2.5 square metres of coverage, making it ideal for both small garden ponds and larger wildlife ponds.

Key Benefits

• Excellent natural oxygenator

• Helps reduce algae and blanketweed growth

• UK native aquatic plant

• Free floating and easy to grow

• Provides shelter for fish and amphibians

• Ideal for wildlife ponds

• Improves water quality naturally

• Suitable for ponds up to 1.5m deep

• Hardy throughout the UK

• Requires no planting baskets or aquatic soil

Reasons to Buy

• One of the most effective oxygenating pond plants available

• Helps create clearer and healthier pond water

• Perfect for wildlife ponds and natural ecosystems

• Extremely easy to establish

• Provides valuable underwater habitat

• Suitable for both new and established ponds

Grows Well With

Hornwort combines exceptionally well with a wide range of pond plants, helping create a balanced pond ecosystem.

• Pygmaea Helvola Waterlily – Provides surface cover while Hornwort oxygenates beneath the water.

• Society Garlic (Tulbaghia violacea) – Adds colourful flowers around the pond edge while Hornwort improves underwater conditions.

• Native Wildlife Marginal Pond Pack – Creates ideal habitat for frogs, newts, dragonflies and beneficial insects.

• Water Forget Me Not – Excellent for wildlife friendly pond margins.

• Marsh Marigold – Provides early season colour while Hornwort maintains water quality.

• Pickerel Weed – Adds vertical interest and attracts pollinators.

Care Instructions

Hornwort requires very little maintenance. Simply place it into the pond and allow it to establish naturally.

If growth becomes excessive during the summer months, remove some of the foliage and leave it at the pond edge for 24 hours before composting. This allows any pond creatures sheltering within the plant to safely return to the water.

Hornwort performs best in still or slow moving water and benefits from reasonable water clarity to maximise photosynthesis.

Flowering Period

May to July

Although Hornwort may produce tiny flowers, it is primarily grown for its oxygenating qualities and attractive underwater foliage.

Size and Growing Conditions

Depth: 30cm to 150cm

Growth Rate: Medium

Growth Habit: Free floating submerged oxygenator

Foliage: Dark green feathery underwater foliage

Position: Full Sun or Partial Shade

Water Type: Still or slow moving water

Coverage: Approximately 2.5m² per pack

Hardiness: H5 (-15°C to -10°C)

UK Native: Yes

Wildlife Friendly: Yes

Amphibian Friendly: Yes

Dispatching Your Pond Plants

Hornwort is supplied loose in a bag rather than planted in baskets, as it is a naturally free floating oxygenating plant.

Upon arrival, simply place the Hornwort directly into your pond. No planting baskets, aquatic compost or preparation is required. Each pack provides approximately 2.5 square metres of coverage and can be distributed around the pond as required.

As a living aquatic plant, appearance may vary slightly throughout the growing season.