Persicaria affinis 'Superba'

Common Name: knotweed 
Type: Herbaceous perennial
Family: Polygonaceae
Zone: 5 to 8
Height: 0.50 to 1.00 feet
Spread: 1.00 to 2.00 feet
Bloom Time: July to October
Bloom Description: Pink
Sun: Full sun
Water: Medium
Maintenance: Low
Suggested Use: Ground Cover, Naturalize
Flower: Showy
Tolerate: Deer, Drought


Easily grown in average, medium wet soils in full sun. Tolerates light shade. Best in organically rich, moisture-retentive soils in full sun. Soils should be kept consistently moist.

Noteworthy Characteristics

Persicaria affinis, commonly known as Himalayan bistort, Himalayan knotweed or fleece flower, is a creeping, densely-tufted, mat-forming, herbaceous (semi-evergreen in warm winter climates) perennial of the knotweed family. It is native to the Himalayas in altitudes up to 15,800’ where it creeps over alpine slopes, glacial moraines, rocky areas, wet meadows and stream banks. It produces mostly basal foliage to 4-6” tall, spreading indefinitely over time by trailing stems to 24” wide or more. Narrow, elliptic, deep green leaves (to 3-4” long) are bluish-green beneath. Leaves turn bronze in fall. Five-lobed red flowers bloom July to October on upright cylindrical terminal spikes (each to 2-3” long) atop leafless stems which rise above the foliage to 10-12” tall. Flowers fade to pale pink as they age. After the flowers have turned brown and died, they typically remain in place on the plant providing winter interest. Plants in the knotweed family generally feature stems which are swollen (the knot) at the leaf nodes.

Polygonum affine is a synonym.

Genus name comes from the Latin persica meaning peach-like and sagittata meaning barbed or arrow-shaped in reference to the shape of the leaves.

Specific epithet means related or similar to.

‘Superba’ is a vigorous mat-forming cultivar that features pale pink flowers from midsummer into fall. Flowers mature to pinkish-red with red calyces. Plants form an attractive ground cover.

The cultivar P. affinis ‘Dimity’ is considered to be a synonym of P. affinis ‘Superba’.


No serious insect or disease problems.


Excellent ground cover. Edging for border fronts. Rock gardens. Stream or pond margins. Open woodland areas. Woodland margins. Bulb cover. Containers.