KNOTWEED

Sturdy plants with jointed stems and small white or pink flowers. Some kinds tend to get out of hand and need to be controlled.

persicaria affinis

• Himalayan Knotweed.
• Zones US, MS, LS; USDA 6-8.
• Himalayan native.
• Spreading plant to 1 feet high, 2 feet or more wide.
• Deep green, lance-shaped, finely tooth-edged leaves are mostly basal; they grow 2412 inches long, turn bronze in winter.
• Dense, erect, 2- to 3 inches spikes of bright rosy red flowers bloom in summer, early fall.
• Informal border or ground cover.
• Darjeeling Red forms 3 inches-high foliage mats, has 10 inches spikes of deep pink flowers that age to red; its foliage turns red in fall.
• Dimity sports pale pink flowers and larger leaves than the species.

persicaria alpina(Persicaria polymorpha) Alpine Knotweed

• Zones US, MS, LS, CS; USDA 6-9.
• Native to China, Japan.
• To 46 feet tall, 4 feet wide.
• Forms a bushy clump of rough-textured, lance-shaped, dark green leaves to 8 inches long.
• In summer, sturdy stems are topped by big, fluffy, creamy white flower plumes reminiscent of astilbe.
• Not invasive.
• Tolerates heat and humidity.

persicaria amplexicaulis

• Mountain Fleece.
• Zones US, MS; USDA 6-7.
• Himalayan native.
• Forms a big clumpto 4 feet tall and wide when plants are in flower.
• Medium green leaves are pointed ovals up to 10 inches long.
• Blooms profusely from midsummer to fall, bearing narrow, 4 inches blossom spikes similar to those of lavender (Lavandula) but in a wider range of colorspink, purple, red, white.
• Firetail has bright scarlet flowers.

persicaria bistorta

• Bistort.
• Zones US, MS; USDA 6-7.
• Native to Eurasia.
• Makes a clump to 212 feet tall, 3 feet wide, with broadly oval, medium green, 4- to 12 inches-long leaves.
• Tight, 2- to 3 inches spikes of pale pink or white flowers bloom from late spring until well into summer.
• Superba is a good pink selection.

persicaria capitata

• Pink Knotweed.
• Perennial in Zones US, MS, LS, CS; USDA 6-9; annual elsewhere.
• Himalayan native.
• Tough, trailing ground cover grows 36 inches high, spreading indefinitely both by rooting stems and by self-seeding.
• Oval, 112 inches-long leaves are dark green when new, take on pinkish overtones when mature.
• Leaves of all ages have a bronzy cast that deepens in cooler weather; they discolor and die below 28F.
• Stems and small, round flower heads are pink.
• Blooms almost all year in mild climates.
• Best in confined spots (where it won't be able to spread) or in uncultivated areas.
• No watering needed.

fleece flower

persicaria microcephala

• Perennial.
• Zones US, MS, LS, CS; USDA 6-9.
• Red Dragon is the poster child of the species and a striking addition to a sun- to-part shade bed.
• Dark burgundy foliage is the reason to grow it, although it does have small white flowers in late summer.
• It does not spread underground, remaining in a clump unless a stem bends over and puts down roots.
• Well-behaved to 3 feet tall.

creeping fleece flower

persicaria vacciniifolia

• Zones US, MS, LS; USDA 6-8.
• Himalayan native.
• Prostrate plant forms a foliage mat to 3 inches high, trailing to 2 feet or wider.
• Slender, branching, reddish stems are clothed in oval, 12 inches-long, shiny green leaves that turn red in fall.
• In late summer, 6- to 9 inches flower stalks bear dense, upright, foxtail-like, 2- to 3 inches spikes of rose-pink blossoms.
• Excellent as a bank cover or for draping over a boulder in a large rock garden.

virginia knotweed

persicaria virginiana

• Zones US, MS, LS; USDA 6-8.
• Native to eastern North America, eastern Asia.
• To 24 feet tall, spreading indefinitely by creeping rhizomes.
• Oval green leaves 310 inches long; insignificant flowers.
• The species is rarely found in gardens.
• More commonly seen is 'Painter's Palette', valued for its flashy foliage: Leaves are marbled in green, pale gray- green, and ivory, with a ragged chocolate-maroon V in the center.
• On new growth, the ivory patches are closer to yellow, and the central V-shaped mark has a pink cast.