North America Non-native Plant

Ceratophyllum Submersum

Botanical name: Ceratophyllum submersum

USDA symbol: CESU6

Native status: Not native but doesn't reproduce and persist in the wild

Soft Hornwort: The Feathery Wonder for Your Water Garden If you’re looking to add some underwater magic to your pond or water feature, let me introduce you to one of nature’s most delicate aquatic performers: Ceratophyllum submersum, commonly known as Soft Hornwort or Tropical Hornwort. This graceful submerged plant might ...

Soft Hornwort: The Feathery Wonder for Your Water Garden

If you’re looking to add some underwater magic to your pond or water feature, let me introduce you to one of nature’s most delicate aquatic performers: Ceratophyllum submersum, commonly known as Soft Hornwort or Tropical Hornwort. This graceful submerged plant might just be the missing piece in your aquatic gardening puzzle.

What Exactly Is Soft Hornwort?

Soft Hornwort is a fully aquatic plant that spends its entire life underwater, creating beautiful, feathery displays beneath the surface. Unlike its terrestrial cousins, this plant doesn’t need soil to thrive – it’s perfectly content floating freely or loosely anchored in your water garden. The soft, needle-like leaves grow in whorls around the stem, creating a delicate, almost ethereal appearance that sways gently with water movement.

Where Does It Come From?

This aquatic beauty hails from tropical and subtropical regions around the world, including parts of Africa, Asia, and the Americas. It’s naturally adapted to warm water environments and thrives in climates that mirror its native habitat.

Why Consider Soft Hornwort for Your Garden?

Here’s where this plant really shines – literally and figuratively:

  • Natural water purifier: Acts as a living filter, absorbing excess nutrients and helping maintain water clarity
  • Oxygen producer: Releases oxygen during daylight hours, benefiting fish and other aquatic life
  • Low maintenance: No soil required, minimal care needed
  • Graceful appearance: Adds soft, flowing texture to underwater landscapes
  • Wildlife habitat: Provides shelter and foraging areas for aquatic creatures

The Perfect Growing Conditions

Soft Hornwort is surprisingly easygoing, but it does have some preferences:

  • Climate zones: USDA zones 9-11 (thinks warm thoughts!)
  • Water temperature: Prefers warm water, ideally 70-80°F
  • Light requirements: Moderate to bright light for best growth
  • Water depth: Can grow in various depths, typically 1-8 feet
  • Water quality: Tolerates a wide range of pH levels and water conditions

What Type of Garden Is This Plant Perfect For?

Soft Hornwort is tailor-made for aquatic environments:

  • Ornamental ponds and water gardens
  • Large aquariums and aquascaping projects
  • Natural swimming pools
  • Biofilter systems
  • Wildlife ponds designed to support aquatic ecosystems

Planting and Care Made Simple

Here’s the beauty of Soft Hornwort – it’s refreshingly straightforward:

  • Planting: Simply place plant fragments directly in the water; no soil needed
  • Anchoring: Can float freely or be gently weighted to stay in preferred locations
  • Fertilization: Absorbs nutrients directly from the water column
  • Pruning: Trim as needed to maintain desired size and shape
  • Winter care: In cooler climates, may die back but can regrow from fragments

Things to Keep in Mind

While Soft Hornwort can be a wonderful addition to water gardens, there are a few considerations:

This plant thrives in warm conditions, so gardeners in cooler climates may find it challenging to overwinter outdoors. In zones below 9, consider it an annual addition or bring portions indoors during colder months.

As with any aquatic plant, it’s important to source your Soft Hornwort responsibly and be mindful of local regulations regarding aquatic plants. Some areas have restrictions on certain water plants, so check with your local extension office before adding any aquatic species to natural water bodies.

The Bottom Line

Soft Hornwort offers water gardeners a low-maintenance way to add both beauty and function to their aquatic spaces. Its feathery texture and water-purifying qualities make it a valuable player in pond ecosystems, while its simple care requirements make it accessible to gardeners of all skill levels. Whether you’re creating a tranquil water feature or designing a complex aquatic landscape, this gentle underwater performer might just be the perfect addition to bring your water garden to life.

Ceratophyllum Submersum

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Magnoliidae

Order

Nymphaeales

Family

Ceratophyllaceae Gray - Hornwort family

Genus

Ceratophyllum L. - hornwort

Species

Ceratophyllum submersum L. [excluded]

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA