Description
Pontederia cordata var. lancifolia (sold as Pontederia cordata lanceolata), known as giant pickerel weed, is a tall form of pickerel weed with narrow, lance-shaped leaves that grow more upright than the usual form. From July to September it carries dense spikes of blue flowers.
Giant pickerel weed at a glance
| Botanical name |
Pontederia cordata var. lancifolia (syn. P. lanceolata) |
| Common name |
Giant pickerel weed, narrow-leaved pickerel weed |
| Plant type |
Upright, clump-forming perennial; dies back in winter |
| Height and spread |
About 1–1.5 m tall, up to 50 cm wide |
| Flowers |
Blue, in dense upright spikes, July to September |
| Position |
Full sun |
| Soil |
Fertile loam in shallow water |
| Pond depth |
10–20 cm of water over the crown |
| Hardiness |
RHS H5 – hardy in a cold winter (-15 to -10°C) |
| Native to |
The Americas (not UK native) |
How is it different from ordinary pickerel weed?
It grows taller, to about 1–1.5 m, with narrower, more upright leaves. It suits larger ponds where the ordinary form would look lost.
Where to plant it
- A sunny pond shelf with 10–20 cm of water over the crown
- Larger garden and wildlife ponds
- The back of a marginal planting, for height
Is it good for wildlife?
The flowers attract bees, butterflies and hoverflies, and dragonfly and damselfly 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. Cut the stems back to just above water level in late autumn, as the hollow stems rot and foul the water if left. 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 come in 7 cm, 9 cm, 1 litre and 3 litre bare-root sizes and cost less per plant. The 2x Pot & Compost option is two plants supplied with pots and compost.
