Petasites albus

Petasites albus, also known as white butterbur, is a perennial rhizomatous ground cover plant that thrives in shaded areas and moist environments. It is most beautiful when its roots are in water. In spring, its inflorescences emerge from the ground and elongate into globose spikes adorned with small white and fragrant heads. Large heart-shaped leaves with toothed edges then appear. They are matte green on the front and woolly on the back. It is an interesting plant to bring a touch of lushness to the edge of a water feature in a large garden. However, its tendency to spread should be controlled. Slightly smaller than Petasites hybridus, it, like its cousin, prefers moist soil and dislikes scorching sun.

Petasites albus is native to Northern Europe. In its natural habitat, this powerful herbaceous perennial colonises rocks, wet areas, and shaded ravines.

White butterbur forms a strongly carpeting clump reaching 30 to 60cm (12 to 24in). In theory, it spreads without limits over time, using its powerful creeping rhizome. The plant blooms from March to May, depending on the climate, before the leaves appear. Developing from grey leaves, the inflorescence emerges from the ground, carried by a leafy stem, with alternate, elongated, sessile, and pointed leaves, which are very different from the large basal leaves that will appear after flowering. The inflorescence takes the form of an ovoid and compact cluster, 10 to 25cm (4 to 10in) high. It consists of small female or male heads gathered in panicles. The white flowers, 1cm (0.4in) in diameter, emit a light sweet fragrance reminiscent of honey. The deciduous basal foliage appears at a later stage. It consists of large, veined, kidney-shaped leaves, with rounded lamina, reaching 30 to 50cm (12 to 20in) or more in diameter. Their colour is a matte green, with a whitish bloom due to the presence of fuzz on both sides. They are edged with a regularly toothed margin and have a long hairy petiole.

Petasites albus is a fast-growing plant, useful for adding a lush touch to the boundaries of a very large garden, to colonise a ditch, a cool rockery, or a somewhat neglected moist woodland. Its fragrance will waft into the more 'civilized' areas of the garden and brighten up a slightly dark corner. However, care must be taken to ensure that it does not exceed the designated limits, as it disregards property boundaries and neighbourly rules. Since it loves moisture and dislikes the sun, it can be effortlessly contained by creating a dry rockery in its path, where the sun prevails over shade. It can be paired with snowdrops, Solomon's seal, and well-established peonies.