Culture
Winter hardy to USDA Zones 3-8 where it is best grown in organically rich, consistently moist, moisture-retentive soils in full sun to part shade. Appreciates some part afternoon shade in hot and dry summer climates. Plants typically do not perform well in the southeastern U.S. Shelter plants from strong winds. Propagate by seed or division. Foliage is semi-evergreen (retains some green color in winter) in the milder parts of its growing range.
Noteworthy Characteristics
Bistorta officinalis, commonly known as European bistort, snakeweed or adderwort, is a vigorous, clump-forming, densely-leaved, semi-evergreen perennial of the knotweed family. It is native to northern Europe, Siberia, Japan and Western Asia as far south as the Himalayas. Plants feature a low mound of dense green foliage consisting of broad-ovate, boldly-veined, medium green, mostly basal leaves (4-12” long and 3-5” wide) with white mid-ribs and pointed tips. Foliage somewhat resembles that of the common garden/field weed known as rumex. Narrow, bell-shaped, pale pink to white flowers (each to 1/4” long) appear in a late spring to mid-summer bloom. Flowers are in showy, cylindrical, terminal, bottlebrush-like flower spikes (each to 3-6” long) atop long slender leafless stems which rise well above the basal foliage to 24-30” tall.
Formerly known as Polygonum bistorta which is now considered to be a synonym.
Specific epithet means twice twisted from the Latin words bis meaning twice and tortus meaning twisted in reference to the twisted root system.
‘Superba’ is a vigorous cultivar that produces soft pink flowers over a long period of time. In comparison to species plants, it grows slightly taller (to 36”) and produces slightly larger flowers and flower spikes (to 4-6” long) in a more profuse bloom.
Problems
No serious insect or disease problems.
Uses
Excellent ground cover. Edging for border fronts. Rock gardens. Cottage gardens. Informal gardens. Pond or stream margins. Boggy areas. Containers. Flowers are sometimes grown commercially for the cut flower industry.