Bistorta amplexicaulis
red bistort
Overview
Bistorta amplexicaulis is a clump-forming herbaceous perennial in the knotweed family (Polygonaceae), forming dense mounds of foliage 24–48 inches (60–120 cm) tall and wide. The mid-green leaves are heart-shaped to oval with pointed tips, 4–10 inches (10–25 cm) long, and clasp the stem at the base. From early summer to mid-autumn the plant carries many slender, upright flower spikes 2–6 inches (5–15 cm) long, packed with tiny flowers in shades of red, crimson, pink, or white depending on the selection. The spikes rise well above the foliage on branching stems and are followed by small brown nutlets. The roots form a thick, slowly spreading rhizome. It grows in moist, fertile soil and dies back to the ground in winter, regrowing from the crown in spring. In dry soil the foliage scorches at the edges and flowering is reduced, and the clump expands steadily where conditions suit it.
Native Range
Native to the Himalaya, from Afghanistan and Pakistan east through northern India and Nepal to south-western China, where it grows in damp meadows, forest margins, and stream banks at moderate to high altitude.Suggested Uses
Bistorta amplexicaulis is used in mixed borders, prairie- and meadow-style plantings, damp ground near water, and large containers, where its long flowering season gives mid- to late-season colour. It also works as ground-covering massing in light shade and as a cut flower.How to Identify
Appearance
Size & Dimensions
Height2' - 4'
Width/Spread2' - 4'
Bloom Information
Flowering runs from June to October, often continuing until the first frosts. The dense spikes of small red, pink, or white flowers are rich in nectar and draw bees, hoverflies, and butterflies over a long season. Spent spikes hold their shape and colour as they fade, and light seeding can occur in mild areas.
Detailed Descriptions
Flower Description
red, pink, or whiteFoliage Description
mid-greenGrowing Conditions
Sun Requirements
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Bistorta amplexicaulis grows in full sun to part shade in moist, fertile, humus-rich soil that does not dry out, and it performs steadily in heavy clay. It needs consistent moisture; in dry or poor soil the leaf margins brown and the flowering spikes shorten. Plants are hardy and need no winter protection in most temperate gardens. They are divided in spring or autumn every few years to keep clumps vigorous, and they regrow quickly after division. A spring mulch conserves moisture and feeds the developing crown. The species has few pest or disease problems.Pruning
Dead stems and old foliage are cut to the ground in late winter or early spring before new shoots appear. Removing faded flower spikes through the season prolongs flowering and limits self-seeding. No other pruning is needed.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winterearly spring
Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons