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Narrow-leaf Duckweed

Lemna trisulca

Last reviewed: August 2026

Narrow-leaf Duckweed (Lemna trisulca)
Photo: Kurt Stüber [1] / Wikimedia Commons (CC BY-SA 3.0)

Toxicity unknown

Narrow-leaf Duckweed (Lemna trisulca) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.

The USDA PLANTS Database (opens in new tab) does not flag Narrow-leaf Duckweed as toxic to livestock.

Light

part shade

Water

high

Size

1"–4" H × 1"–4" W

Bloom

Apr, May, Jun

Native to

AL, AR, AZ, CA and 44 more states

Before you buy

Your city may pay you to plant this

Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 437 programs across 44 states, each with a link to the provider and the date we last checked it.

Find rebates in your area

Browse plants for this ecoregion

Puget LowlandMarine West Coast ForestNorthwestern Forested MountainsSierra NevadaSouthern California MountainsNorth American DesertsCentral Basin and RangeMojave Basin and RangeSouthern RockiesArizona/New Mexico MountainsCentral Great PlainsOzark HighlandsNorthwestern Glaciated PlainsNorthwestern Great PlainsGreat PlainsNorthern Glaciated PlainsWestern Corn Belt PlainsNorthern ForestsNorthern Lakes and ForestsNorth Central Hardwood ForestsDriftless AreaSoutheastern Wisconsin Till PlainsCentral Corn Belt PlainsEastern Corn Belt PlainsSouthern Michigan/Northern Indiana Drift PlainsHuron/Erie Lake PlainsNortheastern HighlandsNortheastern Coastal ZoneErie Drift PlainNorthern PiedmontRidge and ValleyInterior River Valleys and HillsEastern Great Lakes Lowlands

Narrow-leaf duckweed is a tiny aquatic plant that floats on the surface of ponds, slow streams, and water gardens. This native plant forms small colonies of delicate, three-lobed leaves that stay submerged or float just below the water surface. It produces inconspicuous flowers in spring and early summer.

In an HOA neighborhood

Narrow-leaf Duckweed takes more care to keep looking intentional in a front yard. Maintenance level: moderate. Consider it for backyard or mid-zone beds rather than the street edge.

Works well in: backyard only.

  • Aquatic plant only suitable for water features
  • Can spread aggressively and cover entire pond surfaces
  • May be considered unsightly when it forms dense mats

Wildlife value

This aquatic plant provides habitat for small aquatic invertebrates and serves as food for waterfowl and fish. It helps oxygenate water and provides cover for aquatic wildlife.

Common questions

How much sun does Narrow-leaf Duckweed need?
Narrow-leaf Duckweed grows best in part shade conditions.
When does Narrow-leaf Duckweed bloom?
Narrow-leaf Duckweed blooms in April, May, and June.
Where is Narrow-leaf Duckweed native?
Narrow-leaf Duckweed (Lemna trisulca) is native to AL, AR, AZ, CA and 44 more states, per the World Checklist of Vascular Plants (Kew).
Is Narrow-leaf Duckweed toxic to livestock?
The USDA PLANTS Database does not flag Narrow-leaf Duckweed as toxic to livestock.
Is Narrow-leaf Duckweed HOA-friendly?
Narrow-leaf Duckweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

Ready to grow Narrow-leaf Duckweed? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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