Description of Petasites japonicus var. giganteus (Giant Japanese Butterbur)

Petasites japonicus var. giganteus is giant Japanese butterbur. It’s grown for huge leaves that give instant cover in damp ground. It’s ideal when you want a bold backdrop in a wet garden.

Appearance

In spring, thick flower spikes can appear before the leaves. Then the leaves unfurl into big rounded plates on stout stems. In rich wet soil, leaves often reach 60cm or more across and the plant can spread wide.

Care Guide

It loves moisture and it needs space. Contain it if you garden small.

• Sun: Part shade is easiest. Full sun is fine if soil stays wet.
• Soil: Rich, damp soil with plenty of organic matter.
• Water: Keep it consistently wet, especially in summer.
• Control: Use a root barrier or plant in a large solid tub sunk into the bog.
• Cut back: Remove tatty leaves through summer and cut down in late autumn or late winter.

A spring mulch of compost helps keep the leaves big and clean.

Suitability for Bog Garden

This suits larger bog gardens where you want height and shade. Use it to hide edges and create a background behind irises and primulas.

In a liner bog, a big container sunk into the substrate is the safest way to enjoy it without it taking over.

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