Pontederia cordata - Pickerel Weed, Pond Marginal Plant

Pontederia cordata, known as pickerel weed, is a marginal pond plant from North America with bright green, heart-shaped leaves and dense spikes of blue flowers from July to September. It holds the RHS Award of Garden Merit.

Pickerel weed at a glance

Botanical name	Pontederia cordata
Common name	Pickerel weed
Plant type	Clump-forming perennial; dies back in winter
Height and spread	Usually 50–120 cm tall (RHS: up to 1.5 m), 50–100 cm wide
Flowers	Blue, in dense spikes up to 15 cm long, July to September
Position	Full sun
Soil	Fertile loam in shallow water
Pond depth	10–15 cm of water over the crown (a 20–25 cm shelf in cold areas)
Hardiness	RHS H5 – hardy in a cold winter (-15 to -10°C)
Native to	Eastern North America (not UK native)

Where to plant pickerel weed

A sunny pond shelf with 10–15 cm of water over the crown
Garden and formal ponds, where the upright leaves give structure
Larger wildlife ponds alongside native marginals

Is pickerel weed hardy?

Yes. The RHS rates it H5, hardy to between -10°C and -15°C. In very cold areas, a deeper shelf of 20–25 cm protects the crown from ice.

Is it good for wildlife?

The flowers are visited by bees, butterflies and hoverflies, and dragonfly larvae climb the stems to emerge. As a non-native plant, keep it to garden ponds and do not plant it in the wild.

How to plant and care for it

Plant in an aquatic basket of loam from late spring, once the water warms. Cut back the leaves as they collapse in autumn and divide clumps every 2–3 years in spring. Koi and ducks may eat young growth.

Which size should I buy?

Bare-root plants (7 cm, 9 cm, 1 litre and 3 litre) arrive without a pot or compost and are the most economical way to plant a group. Potted plants (9 cm, 1 litre and 3 litre) arrive growing in our peat-free compost and give a faster display. Packs of 3 cost less per plant. The 2x Pot & Compost option is two plants supplied with pots and compost.