Star Duckweed: The Tiny Native Aquatic That Packs a Big Punch
If you’re looking to add some natural charm to your water garden or pond, star duckweed (Lemna trisulca) might just be the perfect native plant you’ve been searching for. This delicate aquatic perennial creates beautiful floating mats that look almost magical drifting across the water’s surface.
What Makes Star Duckweed Special?
Star duckweed gets its name from its distinctive three-lobed leaves that resemble tiny green stars. Unlike its more common cousin, regular duckweed, star duckweed often grows just below the water’s surface, creating an ethereal, translucent carpet effect. This native North American plant is a forb—essentially an herbaceous plant without woody stems—that has adapted beautifully to aquatic life.
Where Star Duckweed Calls Home
This adaptable native plant has an impressive range, naturally occurring across Alaska, Canada, and most of the lower 48 states. You’ll find it thriving from coast to coast, including Alberta, Alabama, British Columbia, California, Colorado, Connecticut, and dozens of other states and provinces. It’s truly a continental native that has adapted to diverse climates and conditions.
Important note for New Jersey gardeners: Star duckweed has a rarity status of S2 in New Jersey, meaning it’s imperiled in the state. If you’re gardening in New Jersey and want to include this species, please source it responsibly from reputable native plant suppliers rather than collecting from wild populations.
Why Choose Star Duckweed for Your Garden?
There are several compelling reasons to consider star duckweed for your aquatic landscaping:
- Natural water filtration: Like other aquatic plants, it helps filter and clean pond water
- Rapid coverage: With its quick growth rate, it provides fast results for new water features
- Low maintenance: Once established, it requires minimal care
- Native plant benefits: Supports local ecosystems and wildlife
- Unique appearance: Creates a more interesting visual than standard duckweed
Perfect Garden Settings
Star duckweed shines in several types of garden settings:
- Natural-style ponds and water gardens
- Rain gardens and bioswales
- Bog gardens and wetland plantings
- Wildlife habitat areas
- Educational or demonstration gardens focused on native plants
Growing Conditions and Care
Star duckweed is refreshingly easy to grow if you can meet its basic needs:
Water requirements: As an obligate wetland plant, star duckweed absolutely must have consistent water. It won’t tolerate drought conditions at all.
Light: While it can handle some shade, star duckweed is actually shade intolerant and performs best in full sun to partial sun conditions.
pH and soil: Prefers slightly acidic to neutral water with a pH between 5.7 and 7.0. Since it’s aquatic, traditional soil considerations don’t apply.
Climate: Extremely cold hardy (surviving temperatures as low as -38°F), this plant thrives in USDA hardiness zones 3-10.
Size: This is a petite plant, reaching only about 0.3 feet (roughly 4 inches) in height, making it perfect for smaller water features.
Planting and Propagation
Star duckweed is typically propagated through sprigs rather than seeds, since it rarely produces viable seed. The plant spreads vegetatively at a moderate rate through stolons (horizontal stems). Here’s how to establish it:
- Obtain sprigs from a reputable native plant supplier
- Simply place the sprigs directly on or just below the water’s surface
- Ensure water temperature is appropriate (needs at least 145 frost-free days)
- Allow the plant to establish and spread naturally
Seasonal Interest and Maintenance
Star duckweed offers subtle seasonal interest with its active summer growth period. The small, green flowers bloom in late spring but aren’t particularly showy—this plant is grown for its foliage effect rather than floral display. The fine-textured, porous foliage maintains its green color throughout the growing season.
Maintenance is minimal, but you may need to thin the plants if they spread too aggressively for your space. The good news? Star duckweed has high fire tolerance and is non-toxic, making it a safe choice for family gardens.
Wildlife and Ecosystem Benefits
While star duckweed may not be a major pollinator magnet due to its inconspicuous, wind-pollinated flowers, it provides valuable habitat for aquatic wildlife and contributes to overall wetland ecosystem health. The plant helps oxygenate water and provides cover for small aquatic creatures.
Is Star Duckweed Right for Your Garden?
Star duckweed is an excellent choice if you:
- Have a pond, water garden, or other consistent water feature
- Want to support native plant communities
- Prefer low-maintenance aquatic plants
- Live in USDA zones 3-10
- Appreciate subtle, naturalistic beauty over showy flowers
However, it’s not the right fit if you:
- Don’t have a reliable water source
- Prefer terrestrial plants
- Want dramatic floral displays
- Have very shady water features
Star duckweed proves that sometimes the most beautiful garden additions come in small packages. This native aquatic plant offers an easy way to add authentic, local character to your water features while supporting North American ecosystems. Just remember to source it responsibly, especially if you’re gardening in areas where it may be less common.
