Potamogeton natans
floating-leaved pondweed
Northern hemisphere (Europe, Asia, North America)
Container Friendly
Native to North America
Overview
Potamogeton natans is an aquatic perennial that roots in the mud of still and slow-moving fresh water and sends up long stems to the surface, where it forms a layer of floating leaves. The floating leaves are leathery, oval to elliptic, 1.5–4.5 inches (4–11 cm) long, with a heart-shaped base and a flexible joint where the blade meets the stalk that lets them lie flat on the water. Submerged leaves are reduced to narrow, grass-like blades that often wither by flowering time. Greenish flowers are packed into a dense cylindrical spike 1–2 inches (3–5 cm) long, held just above the water from June to September, and are wind- and water-pollinated. The plant spreads by branching rhizomes rooted in the bed and can form broad floating colonies in water 1–6.5 feet (0.3–2 m) deep. It grows in lakes, ponds, canals, and slow rivers across the northern hemisphere. It is intolerant of fast current, deep shade, and brackish water, and can crowd small ponds where nutrients are high.
Native Range
Potamogeton natans is native across the temperate and cooler northern hemisphere, including Europe, northern Asia, and North America. It grows in still or slow fresh water such as lakes, ponds, ditches, canals, and slow rivers.Suggested Uses
Used in wildlife ponds, lakes, and large water features for surface cover, shade, and shelter for fish and aquatic insects. The floating leaves also reduce algae by shading the water.How to Identify
Appearance
Size & Dimensions
Height1' - 6'6"
Width/Spread2' - 10'
Bloom Information
Flowering spikes appear from June to September, projecting just above the water surface. Pollination is by wind and water rather than insects. Small nut-like fruits follow and float or sink to establish new plants.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-12 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
Grows rooted in fertile mud in still or slow fresh water 1–6.5 feet (0.3–2 m) deep, in full sun to light shade. Clear to slightly turbid water suits it, and it tolerates a wide range of water chemistry but not salt or strong current. In garden ponds it is planted in mud or aquatic baskets and spreads by rhizome to cover the surface. Floating leaves can shade out submerged plants if growth is dense. It dies back to rhizomes and buds in winter and regrows in spring.Pruning
Surface growth can be thinned by raking out excess floating leaves and stems during the growing season. Rhizomes are divided in spring to propagate or contain the colony. Clearing fading foliage in autumn limits debris buildup in the pond.Container Growing
✓ Suitable for container growing