Overview
Petasites japonicus is a perennial herb in the genus Petasites, part of the Asteraceae family. It typically grows around 0.6 m tall. Petasites japonicus grows best in full sun and full shade, and tolerates most soils. Its UK hardiness is rated H7. It is native to Korea China Japan.
About
Petasites japonicus is a perennial herb in the family Asteraceae that flowers in late winter to early spring (February–April). It typically reaches about 0.6 m and tolerates a wide range of light from full sun to full shade. It prefers moist to wet soils across sandy, loamy or clay textures and is fully hardy in UK gardens. All plant parts contain pyrrolizidine alkaloids and are toxic if ingested.
Wikipedia contributors, CC BY-SA 4.0 — Petasites japonicus
About the genus
Petasites is a genus of flowering plants in the sunflower family, Asteraceae, that are commonly referred to as butterburs and coltsfoots. They are perennial plants with thick, creeping underground rhizomes and large rhubarb-like leaves during the growing season.
In the garden
Petasites japonicus is a perennial herbaceous member of Asteraceae native to Korea, China and Japan. It is valued for its early-season flowering in February–April, which appears before many other garden perennials awake. The species is listed in the genus Petasites and is commonly called giant butterbur or fuki. Plant it where soil remains reliably damp: the species accepts sandy, loamy or clay substrates so long as they stay moist or even wet rather than bone dry. It will tolerate full sun through to full shade, though exposure and local conditions will influence vigour. Expect a mature height around 0.6 m. In UK terms its H7 rating means it is fully hardy and will withstand normal winter conditions; the USDA range 5–9 helps place it for climates outside Britain. Use giant butterbur where early flowering is wanted in damp pockets of the garden — stream or pond margins, shaded beds, or damp hollows where many drier-loving perennials struggle. Be cautious when siting near children or pets: the plant contains pyrrolizidine alkaloids and is toxic if eaten, so avoid planting where foraging might occur.
Growing conditions
Best soil and position for Petasites
- Sunlight
- Full sun, Full shade
- Soil type
- Sandy, Loamy, Clay
- Soil moisture
- Moist but well-drained, Wet
- UK hardiness
- H7
Plant details
Petasites japonicus size, habit and characteristics
- Plant type
- perennial herb
- Height
- 0.6 m
- Native to
- Korea China Japan
- Toxicity
- contains pyrrolizidine alkaloids, toxic if ingested
Care notes
Pruning and caring for Petasites japonicus
- Propagation
- division, seed
Frequently asked questions
Where is the best place to plant Petasites japonicus?
Petasites japonicus prefers full sun and full shade.
What soil does Petasites japonicus need?
Petasites japonicus is adaptable and grows happily in most soil types, including sandy, loamy and clay. Aim for soil that stays moist but well-drained to wet.
How big does Petasites japonicus grow?
Petasites japonicus reaches a height of 0.6 m.
Is Petasites japonicus hardy in the UK?
Petasites japonicus has an RHS hardiness rating of H7, meaning it is fully hardy throughout the UK, tolerating temperatures below -20°C.
How do I propagate Petasites japonicus?
Division, seed.
Is Petasites japonicus toxic?
Contains pyrrolizidine alkaloids, toxic if ingested.
