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Common Duckweed

Lemna minor (LEM-nuh MY-nor)

Family: Araceae Native Groundcover (<1 ft)

Common Duckweek is a small, aquatic, herbaceous perennial in the arum family reaching only 3 inches high, but when grouped together, these tiny plants form a floating carpet cover on the water's surface. Flowering is rare and it is among the smallest flowering plants known. Each plant consists of a single flat leaf that floats on the surface of still waters such as ponds and lakes. The common name comes from the fact that ducks, along with other waterfowl, like to eat it. Common Duckweed prefers full sun or partial shade and a standing water environment. It has a short lifespan, but spreads rapidly, Its habit is to lay along the water surface with its extremities facing upwards. Duckweed can grow on wet mud and will overwinter at the bottom or ponds. As the weather warms in spring, buds will rise to the surface. A sticky secretion from the pistol of the plants' flower attracts flies, mites, spiders, and bees. Their contact with the substance leads to further pollination of the plant. Although some consider its spreading nature as invasive, there are some benefits. Waterways containing high amounts of phosphorus and nitrogen from agricultural runoff can be controlled by harvesting duckweed. The plant helps remove these pollutants from the water. It also discourages algae growth in water gardens and ponds. Clemson University Home and Garden Information Center has a factsheet on aquatic weed control, including advice on controlling duckweed. Insects, Diseases and Other Plant Problems: Its spreading nature can become invasive.

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 48 attributes.

How it fits the guild

Guild layer 5 - Groundcover (<1 ft)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Often confused with Azolla caroliniana

Full plant profile

Growing Conditions
Plant type
Herbaceous Perennial; Native Plant; Water Plant
Life cycle
Perennial
USDA zones
4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil drainage
Frequent Standing Water
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 0 ft. 3 in. - 0 ft. 3 in. | Width: 1 ft. 0 in. - 3 ft. 0 in.
Growth rate
Rapid
Maintenance
Medium
Canopy layer
5 - Groundcover (<1 ft)
Form & Appearance
Habit / form
Dense; Spreading
Texture
Fine
Leaf color
Green
Leaf type
Fronds
Leaf shape
Ovate
Leaf margin
Entire
Leaf feel
Fleshy; Smooth
Leaf size
< 1 inch long
Hairs present
No
Leaf detail
Each plant consists of a bright green, 1/4 inch, oval-rounded, flattened green frond with a single downward-trailing root.
Flower color
Green; White
Flower form
Insignificant; Spadix
Flower shape
Cup
Flower size
< 1 inch
Flower detail
Flowers are rare and small.
Bloom time
Summer
Fruit detail
The fruit is a utricle.
Stem detail
One small rootlet
Wildlife & Ecology
Native status
Native
Origin
Native Worldwide
Distribution
Distributed to Australia
Wildlife value
Attracts birds. Food source for ducks, tadpoles, fish, and beavers.
Attracts
Songbirds
Play value
Attracts Pollinators; Wildlife Food Source
Food & Medicine
Harvest time
Summer

Uses (ethnobotany)

Used as animal food.

Landscape Use
Landscape location
Coastal; Pond
Landscape theme
Native Garden; Rain Garden; Water Garden
Garden tags
#NC native #spadix #water garden #tiny leaves #perennial #pond #herbaceous perennial #spreading #standing water tolerant #aquatic
Problems & Resistance
Problems
Weedy
Propagation
Seed

Planted at Hunnicutt

Nobody’s planted this one yet.