Wolffia borealis (Engelm.) Landolt

• Genus: Wolffia
• Botanical Background: Originally described by botanist George Engelmann, the species was later reclassified by Swiss botanist Elias Landolt, a key authority on Lemnaceae and duckweeds.

• Geographical Range: Native to freshwater habitats throughout North America, including parts of Canada and the northern United States.
• Environment: Thrives in calm, nutrient-rich freshwater bodies such as ponds, lakes, and slow-moving streams. Prefers full sun and grows best in temperate climates during the warmer months.

Leaves

• No true leaves; plant consists of a minute, bright green, oval to spherical frond

• Typically less than 1 mm across and floats on the water’s surface

Inflorescence (Spadix & Spathe)

• Flowers are extremely rare and highly reduced

• Single floral structure forms without a visible spathe; pollination likely occurs via selfing or water dispersion

Growth Habit

• Fully aquatic and free-floating

• Lacks roots and stems; reproduces through vegetative budding of daughter fronds

Light Requirements

• Thrives in full sun for optimal growth and reproduction

• Can tolerate partial shade, though it may reduce budding rates

Watering & Humidity

• Requires freshwater environments, either standing or slow-moving

• High humidity and constant water immersion are essential

Soil & Potting Mix

• No soil needed; grows freely on the water surface

• In cultivation, use shallow trays or tanks with nutrient-rich water

Temperature & Fertilizer

• Prefers warm temperatures: 68–86°F (20–30°C)

• Aquatic plant fertilizer can support growth, especially indoors or in research setups

Division

• Reproduces quickly through vegetative budding

• Parent fronds generate daughter plants that detach and float freely

Stem Cuttings (if applicable)

• Not applicable; lacks stems and roots

Seeds

• Seed production is extremely rare and not typically used

• Low viability and infrequent flowering limit seed-based propagation

Typical Issues

• Generally resistant to pests

• Stagnant water can cause algal blooms or harmful anaerobic conditions

Treatment Recommendations

• Maintain clean, well-oxygenated water to support healthy growth

• Control algae through manual removal or nutrient balance

• Avoid chemical treatments to protect aquatic ecosystems

• Wolffia borealis is one of the world’s smallest flowering plants

• Serves as a food source for waterfowl and acts as a bioindicator of water quality

• Not typically grown for ornamental purposes

• Valued in ecological and scientific research for its simplicity, rapid reproduction, and potential in wastewater treatment and biomass applications

Wild Population Status

• Not currently listed as threatened

• Populations are stable in natural freshwater habitats across North America

Market Availability

• Occasionally available through aquatic plant suppliers

• Primarily distributed for research purposes or specialized aquatic collections