Illinois Pondweed Identification & Treatment
Scientific Name: Potamogeton illinoensis Category: Submerged Tier: 3 — Localized — Native species, regionally significant
← Back to Plant Identification Guide | Product Cross-Reference | Ecoregion Guide
Identification
Illinois pondweed has broad, elliptical submerged leaves and may produce floating leaves in shallow water. Leaves are alternate, with prominent veins and a slightly wavy margin. Stems are branching and can grow several feet long. Key distinguishing features:
- Broad, elliptical submerged leaves (2–6 inches long)
- Alternate leaf arrangement
- Prominent leaf veins
- May produce floating leaves in shallow water
Commonly confused with: American Pondweed (floating leaves more leathery), Curly-Leaf Pondweed (wavy/crinkled margins, not just slightly wavy)
Treatment
Illinois pondweed is a native species with significant habitat value. Selective treatment is recommended only when overgrowth impairs pond function.
- Aquathol K (endothall) — Contact treatment for spot control.
- Navigate or Sculpin (2,4-D) — Selective systemic option.
Full Profile
- Native Range: North America
- US Distribution: Eastern and central United States. USDA Zones 4–9.
- Regulatory Status: Not regulated (native).
- Habitat: Ponds, lakes, and slow streams with moderate water clarity.
- Reproduction: Spreads by rhizomes and seed.
- Ecological Benefits: Valuable habitat for fish and invertebrates. Seeds and tubers provide food for waterfowl. Helps maintain water clarity.
Sources: Texas A&M AquaPlant | USDA PLANTS Database
Related Species
- American Pondweed (Potamogeton nodosus) — Submerged, Tier 1
- Curly-Leaf Pondweed (Potamogeton crispus) — Submerged, Tier 1
- Sago Pondweed (Stuckenia pectinata) — Submerged, Tier 2
← 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.