Pontederia cordata (Pontederia lanceolata)Pickerel Weed

Pontederia cordata is the standard flowering marginal for a still-water edge. Glossy heart-shaped leaves stand clear of the surface on strong stalks, and through summer the clump throws dense spikes of violet-blue flowers, held well above the foliage. Narrow-leaved plants are sometimes offered as Pontederia lanceolata, a name now treated as a synonym of P. cordata.

It grows in saturated soil or in standing water to about 300 millimetres deep, spreads steadily by rhizome, and holds a pond margin against wave wash better than most planted alternatives.

Specifications

• Height0.6 to 1.2 metres above the water surface
• Width0.5 to 1 metre per clump, spreading by rhizome
• Native toThe Americas, from eastern North America south to South America
• FoliageGlossy, heart-shaped emergent leaves on strong upright stalks; deciduous in cool climates and evergreen in warm ones
• Growth rateFast

Conditions

• SoilGrows in saturated loam or heavy soil, in aquatic baskets or directly in a lined margin
• LightFull sun to partial shade
• WaterPermanently wet; standing water to about 0.3 metres deep
• ClimateThrives from temperate through to subtropical regions

Additional Features

• FlowersDense spikes of violet-blue flowers held above the foliage through summer
• UsesPond and lake margins, constructed wetlands, rills, water features and bioretention basins
• SpacingPlant 0.4 to 0.5 metres apart for a continuous margin
• Low MaintenanceCut back spent foliage annually and divide congested clumps every few years
• Pest ResistanceGenerally trouble free
• Wildlife AttractionFlowers are worked by bees, and the clump gives cover to dragonflies and amphibians
• Erosion ControlRhizome mats hold a soft margin against wave wash

Pickerel Weed is the dependable flowering marginal, giving a still-water edge both structure and a long blue season.