Pontederia cordata
pickerelweed
Overview
Pontederia cordata is an emergent aquatic perennial growing 24-48 inches (60-120 cm) tall from a creeping rhizome rooted in mud at the water margin. Glossy, heart-shaped to lance-shaped leaves 4-10 inches (10-25 cm) long rise on long stalks above the water surface. Dense flower spikes 3-6 inches (8-15 cm) long carry many small violet-blue tubular flowers from June to October, each upper lobe marked with a pair of yellow spots. Flowers open a few at a time from the base upward, and each lasts a single day. The fruit is a small ribbed nutlet that drops into the water and can float to new sites. Plants spread by thick rhizomes to form colonies in standing or slow-moving water up to 12 inches (30 cm) deep. Foliage dies back to the rhizome after frost and re-emerges in spring. Growth is limited to permanently wet ground or shallow water, and plants will not survive in dry soil. The starchy seeds and young leaves have been eaten historically.
Native Range
Native to eastern and central North America from Nova Scotia and Ontario south to Florida and Texas, and into the Caribbean and South America. Grows in shallow margins of ponds, lakes, slow streams, marshes, and ditches in fresh water.Suggested Uses
Used at pond and lake margins, in rain gardens, bog gardens, and constructed wetlands, spaced 12-24 inches (30-60 cm) apart in water up to 12 inches (30 cm) deep. Suits naturalistic water features and wildlife ponds where the flowers draw bees. Unsuited to dry borders or containers without standing water.How to Identify
Appearance
Size & Dimensions
Height2' - 4'
Width/Spread1'6" - 2'
Bloom Information
Flowers from June through October, with the heaviest bloom in midsummer. Each flower lasts one day, but spikes produce new flowers in succession over several weeks. Bloom continues over a longer span in warm climates and is briefer where the season is cool and short.
Detailed Descriptions
Flower Description
violet-blue with yellow spotsFoliage Description
glossy greenGrowing 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
Grows in full sun to partial shade in permanently saturated soil or standing water up to 12 inches (30 cm) deep. Plants need consistently wet conditions and decline rapidly if the root zone dries. In ponds, grow in mesh baskets of heavy loam topped with gravel to limit rhizome spread, or set plants directly into pond-margin mud. Cut back dead foliage in late fall or early spring. Rhizomes spread steadily and can be divided every 2-3 years to control colony size. No serious pests affect it, though leaves may be chewed by aquatic insects.Pruning
Remove spent flower spikes through the season to limit self-seeding into the water. Cut foliage to the waterline in late autumn after frost or in early spring before new growth. Divide congested rhizome colonies in spring to maintain colony size.Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons