Persicaria decipiens

Persicaria decipiens, or Slender Knotweed, is a semi-aquatic perennial herb in the family Polygonaceae, native to Australia. Commonly found in wetlands, along riverbanks, and in seasonally inundated areas, it grows up to 80 cm high with sprawling or upright stems. Its lance-shaped green leaves are often widest in the middle and may feature dark blotches and bristles along the margins and main veins, adding visual interest to the plant’s herbaceous appearance. A distinctive feature is the ochrea, a membranous tube that surrounds the stems at the base of the leaves, characteristic of the genus Persicaria.

From December to April, Slender Knotweed produces delicate linear clusters of small, deep pink to reddish flowers, measuring 2–6 cm long, which stand out against wetland environments. These are followed by shiny, dark brown to black nut-like fruits, which are round to triangular in shape and aid in dispersal.

Thriving in moist to waterlogged soils and tolerating full sun to partial shade, Slender Knotweed is highly adaptable and well-suited for wetland rehabilitation, riparian planting, and erosion control. Its spreading habit stabilizes soil, prevents erosion, and improves water quality by filtering sediments, making it a valuable species for ecological restoration projects.

With its delicate flowers, unique foliage features, and ecological benefits, Persicaria decipiens is an excellent addition to water-sensitive landscaping and biodiversity-focused designs. Its ability to enhance wetland aesthetics while contributing to habitat and ecosystem health makes it a standout species for naturalistic and restoration plantings.