Potamogeton polygonifolius
bog pondweed
Western and central Europe, North Africa, eastern North America
Container Friendly
Native to North America
Overview
Potamogeton polygonifolius is a perennial aquatic plant of the family Potamogetonaceae, rooting in mud and producing both floating and submerged leaves from a creeping rhizome. The floating leaves are oval to elliptic, leathery, 1.2–4.7 inches (3–12 cm) long, on long stalks, and often tinged red-brown; the submerged leaves are narrower, thinner, and translucent. Stems reach 4–24 inches (10–60 cm) depending on water depth, and the plant also creeps over wet mud where pools dry out, forming a land state with smaller leaves. Greenish flowers are crowded in dense cylindrical spikes 0.4–1.2 inches (1–3 cm) long held just above the water from May to October, and are wind- and water-pollinated. The fruit is a small reddish drupelet about 2 mm long. It grows in shallow, still or slow-moving, acid and nutrient-poor water of bog pools, ditches, peaty streams, and moorland flushes. The species declines where water is enriched with nutrients or lime and does not persist in deep shade or fast current.
Native Range
Native to western and central Europe, parts of North Africa, and eastern North America, growing in soft, acid waters. It is widespread across the Atlantic regions of Europe and absent from hard, calcareous waters.Suggested Uses
Potamogeton polygonifolius is used in wildlife ponds, bog gardens, and acid pool restoration, where its floating leaves give cover for aquatic insects, tadpoles, and small fish. It also stabilises soft sediment in shallow moorland pools.How to Identify
Appearance
Size & Dimensions
Height4" - 2'
Width/Spread1' - 2'
Bloom Information
Flowering runs from May to October, peaking in summer. The small greenish flowers are packed into cylindrical spikes 0.4–1.2 inches (1–3 cm) long raised above the water and pollinated by wind and water movement. Reddish single-seeded fruits ripen through late summer and float briefly before sinking.
Detailed Descriptions
Foliage Description
green, often tinged red-brownGrowing Conditions
Sun Requirements
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Potamogeton polygonifolius grows in full sun to part shade in shallow, soft, acid water 2–24 inches (5–60 cm) deep over peaty or sandy mud. It needs low-nutrient, lime-free conditions and declines quickly in enriched or alkaline water. In cultivation it suits acid pool margins and bog gardens, where it is planted into mud in containers or directly in the substrate and left undisturbed. It dies back to rhizomes and turions over winter and regrows in spring. No feeding is given, as added nutrients favour algae and competing plants.Pruning
No routine pruning is required. Thinning overgrown floating stems in summer keeps the water surface partly open, and removing fallen leaves in autumn limits nutrient build-up in small pools.Container Growing
✓ Suitable for container growing
Minimum container size: 2 gallons