North America Non-native Plant

Ricefield Waternymph

Botanical name: Najas graminea

USDA symbol: NAGR2

Life cycle: annual

Habit: forb

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Synonyms: Caulinia graminea (Delile) Tzvelev (CAGR18)   

Ricefield Waternymph: A Unique Aquatic Plant for Water Gardens If you’re looking to add some underwater greenery to your pond or water feature, you might have come across the ricefield waternymph (Najas graminea). This interesting little aquatic plant has been making its way into California’s waterways and gardening conversations. But ...

Ricefield Waternymph: A Unique Aquatic Plant for Water Gardens

If you’re looking to add some underwater greenery to your pond or water feature, you might have come across the ricefield waternymph (Najas graminea). This interesting little aquatic plant has been making its way into California’s waterways and gardening conversations. But is it right for your garden? Let’s dive in and explore this submerged wonder.

What Exactly is Ricefield Waternymph?

Ricefield waternymph, scientifically known as Najas graminea, is a completely submerged aquatic plant that looks quite a bit like underwater grass. You might also see it listed under its synonym Caulinia graminea in some older gardening references. This annual forb lacks any woody tissue and spends its entire life cycle underwater, making it a true aquatic specialist.

As its name suggests, this plant has historically been associated with rice fields in its native range, where it grows as a submerged weed. The waternymph part of its name comes from the genus Najas, which refers to water nymphs in Greek mythology – quite fitting for a plant that lives its entire life beneath the water’s surface!

Native Status and Where It Grows

Here’s where things get interesting: ricefield waternymph isn’t actually native to North America. This plant originally hails from parts of Africa and Asia, but it has established itself in California, where it now reproduces on its own in the wild without any human help. It’s what we call a naturalized non-native species.

Currently, you’ll find this plant growing in California’s waterways, where it has adapted quite well to local conditions. It’s classified as an obligate wetland species, meaning it almost always occurs in wetland environments – no surprise there, since it can’t survive outside of water!

Should You Plant Ricefield Waternymph?

This is where gardeners need to think carefully. While ricefield waternymph isn’t currently listed as invasive or noxious, its non-native status means it’s not providing the same ecological benefits that our native aquatic plants would offer. If you’re planning a water garden or pond, you might want to consider native alternatives first.

That said, if you do choose to grow ricefield waternymph, it can serve some useful purposes in aquatic settings. It provides underwater structure and can help with water clarity in ponds and aquariums.

What Does It Look Like?

Ricefield waternymph is quite modest in appearance. Picture thin, grass-like leaves that remain completely submerged throughout the plant’s life. The plant forms dense, underwater carpets that can look quite attractive in the right setting. Since it’s an annual, individual plants complete their entire life cycle in one growing season, though they readily self-seed to continue the population.

Growing Conditions and Care

If you decide to grow ricefield waternymph, here’s what you need to know:

  • Water requirements: Must be completely submerged at all times
  • Light: Prefers full to partial sun filtering through the water
  • pH: Tolerates neutral to slightly alkaline water
  • Temperature: Best in USDA zones 9-11, though it may grow as an annual in cooler areas
  • Depth: Can grow in various water depths from shallow to moderately deep

Planting and Maintenance

Growing ricefield waternymph is relatively straightforward once you understand its needs. You can plant it directly in pond substrate or weighted containers placed in your water feature. The plant will establish itself quickly if conditions are right.

Since it’s an annual, don’t expect individual plants to return year after year. However, if allowed to complete its reproductive cycle, new plants will likely appear the following season. Regular monitoring is important to ensure it doesn’t spread beyond your intended growing area.

Wildlife and Pollinator Benefits

While ricefield waternymph does provide some habitat structure for aquatic creatures, its benefits to local wildlife are limited compared to native aquatic plants. As a non-native species, it hasn’t co-evolved with our local ecosystem, so native birds, insects, and other wildlife won’t rely on it as a food source or nesting material.

The Bottom Line

Ricefield waternymph can be an interesting addition to water gardens for those who appreciate unique aquatic plants. However, if you’re focused on supporting local wildlife and maintaining ecological balance, consider exploring native aquatic alternatives first. California has many beautiful native water plants that would provide similar aesthetic appeal while supporting local ecosystems.

If you do choose to grow ricefield waternymph, do so responsibly by keeping it contained within your water feature and preventing its spread to natural waterways. Remember, being a thoughtful gardener means considering not just what looks good in our gardens, but what’s good for our local environment too!

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Arid West

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Western Mountains, Valleys, and Coast

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Ricefield Waternymph

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Alismatidae

Order

Najadales

Family

Najadaceae Juss. - Water-nymph family

Genus

Najas L. - waternymph

Species

Najas graminea Delile - ricefield waternymph

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