Description of Pontederia lanceolata (Giant Pickerel Weed)

Pontederia lanceolata is giant pickerel weed, a taller, chunkier cousin of standard pickerel weed. It’s grown for upright leaf clumps and long blue flower spikes in summer, and it suits pond shelves and very wet bog corners.

Appearance

Leaves are long and lance-shaped, held upright on strong stalks. Flower spikes are blue to violet and appear in mid to late summer. In warm, wet conditions it can reach around 1 to 1.5m tall, so it reads as a background marginal.

Care Guide

Grow it as a true marginal, with constant water around the roots. It responds well to feeding in baskets.

• Sun: Full sun gives the best height and flower spikes.
• Soil: Aquatic compost in a deep basket, topped with gravel.
• Water depth: Shallow water over the soil line, often around 10 to 40cm.
• Feeding: Aquatic fertiliser tablets through summer help flowering.
• Tidy up: Cut back old stems in late winter.

Divide in spring if the clump becomes too large for its basket. Replant firm sections and keep them wet while they settle.

Suitability for Bog Garden

This suits larger bog gardens and ponds where you want a tall structural plant that flowers in summer. It’s great behind lower marginals like water forget-me-not and marsh marigold.

In smaller bog beds, it can still work if you give it a back corner and keep it in a basket so it doesn’t crowd everything else.

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