Petasites albus is a perennial herb in the Asteraceae, notable for its rounded leaves and compact heads of white composite flowers. It grows to around 0.6 m. In the UK it flowers from February to April. It tolerates both full sun and dense shade and prefers moist but well-drained sandy, loamy or clay soils.

White butterbur (Petasites albus) is a perennial that produces white flower clusters from February to April and suits moist, shaded sites.

https://en.wikipedia.org/wiki/Petasites_albus

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.

Petasites albus

White butterbur | Petasites albus

Petasites fragrans is a perennial in the Asteraceae that forms a spreading ground cover and produces fragrant flowers in February to April. It prefers partial shade or shade on moist, well-drained soils and has a UK hardiness of H7 (fully hardy). Suited to woodland planting and shady borders, it performs best where the soil remains reliably damp. The flowers are scented and appear early in the season.

Winter heliotrope (Petasites fragrans) features scented flowers from February to April and suits moist, shady ground-cover planting.

https://en.wikipedia.org/wiki/Petasites_pyrenaicus

Petasites fragrans

Winter heliotrope | Petasites fragrans

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.

Giant butterbur (Petasites japonicus) is a fully hardy perennial that flowers February–April and prefers moist to wet soils in sun or shade.

https://en.wikipedia.org/wiki/Petasites_japonicus

Petasites japonicus

Giant butterbur | Petasites japonicus

Petasites × hybridus is a perennial herb in the Asteraceae grown for ground cover in damp, sheltered spots. It favours moist to wet, neutral to slightly acidic soils and performs in partial to full shade. Flowering occurs February to April in the UK. The plant contains pyrrolizidine alkaloids and is toxic if ingested.

Butterbur (Petasites × hybridus) suits moist, sheltered shade and neutral to slightly acidic soils and flowers February to April.