Water Lilies Identification & Treatment
Scientific Name: Nymphaea spp. (fragrant water lily N. odorata, others) and Nuphar spp. (spatterdock/cow lily) Category: Floating (rooted) Tier: 1 — High-Priority — Most prevalent and/or most damaging across the US
← Back to Plant Identification Guide | Product Cross-Reference | Ecoregion Guide
Identification
Fragrant Water Lily (Nymphaea odorata): Large, round floating leaves (4–12 inches) with a V-shaped notch (sinus) cut to the center. Leaves are green above, often purplish below. Produces showy white (sometimes pink) multi-petaled flowers that float on or just above the surface. Stems arise from thick rhizomes rooted in bottom sediment. Spatterdock / Cow Lily (Nuphar advena, N. lutea): Heart-shaped floating and emergent leaves, thicker and more leathery than water lily. Produces small, yellow, globe-shaped flowers that barely open. Leaf sinus is more open (wide V or U-shape).
Key distinguishing features:
- Large, round or heart-shaped floating leaves with a cut (sinus) to the center
- Nymphaea: V-notch sinus, white/pink flowers, thinner leaves
- Nuphar: Wide sinus, yellow globe flowers, thicker leaves, leaves sometimes stand above water
Commonly confused with: Watershield (smaller oval leaves with no sinus, gelatinous coating underneath), floating heart (much smaller leaves, fringed flowers), American lotus (leaves much larger, often cupped and held above water)
Treatment
Recommended Natural Waterscapes Products:
- Navigate Granular (2,4-D) — The primary treatment for water lilies. Systemic granular that sinks to the root zone and kills rhizomes. Apply during active growth (spring/early summer). Navigate
- Harvester (diquat) — Contact herbicide that will kill pads but may not reach rhizomes. Good for quick aesthetic cleanup. Harvester
- LakeMat Pro — Non-chemical bottom barrier that blocks growth. LakeMat Pro
Full Profile
- Native Range: Both Nymphaea odorata and Nuphar advena are native to North America.
- US Distribution: All 48 contiguous states. All EPA ecoregions. USDA Zones 3–11.
- Regulatory Status: Not regulated (native species).
- Habitat: Ponds, lakes, sheltered bays, slow streams. Grows in 2–6 feet of water (water lilies) or up to 8 feet (spatterdock).
- Reproduction: Thick rhizomes and seed. Rhizome fragments can establish new colonies.
- Ecological Benefits: Extremely valuable ecologically. Water lily pads provide shade that reduces water temperature and algae growth. Flowers are critical pollinator habitat. Pads provide perching and basking sites for frogs, turtles, and dragonflies. Root systems stabilize sediment. Seeds, rhizomes, and foliage are food for beaver, muskrat, moose, and waterfowl. Fish use the shaded understory for cover. In most situations, water lilies should be managed rather than eliminated — selective removal to maintain open water channels while preserving some lily coverage is usually the best approach.
- Seasonal Behavior: Emerge in spring, peak coverage in summer, die back in fall. Rhizomes survive winter.
Sources: Texas A&M AquaPlant – Water Lily | Texas A&M AquaPlant – Cow Lily | USDA PLANTS Database
Related Species
- Watershield (Brasenia schreberi) — Floating (rooted), Tier 2
- Floating Heart (Nymphoides spp. (N. peltata — yellow floating heart; N. cristata — crested floating heart)) — Floating (rooted), Tier 2
- Hydrilla (Hydrilla verticillata) — Submerged, Tier 1
- Eurasian Watermilfoil (Myriophyllum spicatum) — Submerged, Tier 1
- Duckweed (Lemna minor and related species (L. gibba, L. turionifera, Spirodela polyrhiza)) — Floating, Tier 1
- Watermeal (Wolffia spp. (W. columbiana, W. brasiliensis)) — Floating, Tier 1
← Back to Plant Identification Guide | Product Cross-Reference | Beneficial Considerations
Natural Waterscapes — Expert Aquatic Plant Identification & Treatment Need help identifying a plant? Send us a photo and our experts will identify it for you.