Persicaria alpina (Alpine Knotweed)

Persicaria alpina (Alpine Knotweed) is a tall semi-evergreen, perennial boasting sturdy branching stems clothed with large, lance-shaped, green leaves. In midsummer, stately plumes of small creamy-white flowers are on display for weeks, if not months.

Persicaria alpina (Alpine Knotweed) is a tall semi-evergreen, perennial boasting sturdy branching stems clothed with large, lance-shaped, green leaves. In midsummer, stately plumes of small creamy-white flowers are on display for weeks, if not months. They are followed by pinkish-red seed heads in late summer. Clump-forming and low maintenance, this spectacular perennial is tolerant of heat, humidity, and, once established, some drought. Unlike other species of Persicaria, it is not considered invasive, but it does require some room to grow. Perfect for the back of the border or as a flowering hedge.

  • Recipient of the prestigious Award of Garden Merit of the Royal Horticultural Society
  • Grows up to 3-5 ft. tall and wide (90-150 cm) and 3-4 ft. wide (90-120 cm). Provide ample room for it to grow to its full potential.
  • Thrives in any moist soils in full sun or partial shade.
  • This is a welcomed addition to beds and borders, city gardens, cottage gardens, and gravel gardens. This is also an ideal candidate along ponds and streams or in naturalistic meadows.
  • Low maintenance, it is also pest and disease free. Deer resistant.
  • Cut back after flowering.
  • All plant parts may cause skin irritation on contact and stomach upset if ingested.
  • Native to the Himalayas.

Requirements

Hardiness 4
– 9

Plant Type Perennials
Plant Family Persicaria – Fleeceflowers
Exposure Full Sun, Partial Sun
Season of Interest Summer (Mid,Late)Fall
Height 3'
– 5'
(90cm
– 150cm)
Spread 3'
– 4'
(90cm
– 120cm)
Spacing 36″
– 48″
(90cm
– 120cm)
Water Needs Average, High
Maintenance Low
Soil Type Clay, Loam
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained, Poorly Drained
Characteristics Cut Flowers, Plant of Merit, Showy, Semi-Evergreen
Tolerance Deer, Drought
Garden Uses Beds and Borders, Hedges and Screens, Wall-Side Borders
Garden Styles City and Courtyard, Gravel and Rock Garden, Informal and Cottage, Prairie and Meadow