Bistorta amplexicaulis

Bistorta amplexicaulis (synonym Persicaria amplexicaulis), the red bistort or mountain fleece, is a species of flowering plant in the buckwheat family Polygonaceae, native to China, the Himalayas, and Pakistan. It is a damp-loving herbaceous perennial growing to 1.2 m tall and wide, with heart-shaped pointed leaves, downy beneath, and narrow spikes of rose-red or white flowers in summer.

Numerous cultivars have been developed for garden use, including 'Firetail'.

Etymology
The Latin specific epithet amplexicaulis means "clasping or embracing the stem", and refers to the leaves' habit of growing around the stem.