Persicaria microcephala 'Red Dragon'
Common Name: knotweed 
Type: Herbaceous perennial
Family: Polygonaceae
Zone: 6 to 8
Height: 2.00 to 2.50 feet
Spread: 2.50 to 3.00 feet
Bloom Time: July to August
Bloom Description: White
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Flower: Showy, Good Cut
Leaf: Colorful
Attracts: Butterflies
Tolerate: Rabbit, Deer


Best grown in moist, moderately fertile, well-drained soils in full sun to part shade. Soils should be kept evenly moist. Species plants will spread in the garden by stolons.

‘Red Dragon’ is a clump-forming sterile cultivar which lacks the spreading stoloniferous characteristics of species’ plants.

Noteworthy Characteristics

Persicaria microcephala, commonly known as knotweed or fleeceflower, is an herbaceous perennial that typically grows to 24” tall. It is native to forests and grassy areas in China. It is a stoloniferous spreader that is noted for having green stems clad with broad-ovate to triangular-ovate green leaves (to 2-4” long), each leaf being decorated with a lighter green chevron. Leaves remain green throughout the growing season. Campanulate white flowers (each to 1 1/4” long) bloom in late summer. Polygonum microcephalum 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 comes from Greek meaning small-headed in reference to flower size.

‘Red Dragon’ is a cultivar that typically grows to 30” tall and to 36” wide. In comparison to species’ plants, it is distinguished by having (a) red stems, (b) leaves which emerge purple-brown with a gray-brown to mint green chevron in spring, with the leaves turning silver-purple and finally green with maturity, and (c) a clump-forming rather than stoloniferous habit. ‘Red Dragon’ was discovered as a naturally occurring mutant seedling that appeared in a crop of Persicaria microcephela being grown for medicinal purposes in Nanjing, China. Pollen and seed parents are Persicaria microcephala. First asexual reproduction of ‘Red Dragon’ occurred in April of 1997 when the inventor, C. Greg Speichert, took cuttings of this new plant in St. John, Indiana. Flowers bloom July-August. U.S. Plant Patent PP12,062 was issued on August 21, 2001.


No serious insect or disease problems.


Mass woodland or cottage gardens. Borders. Mixed containers.