Aconogonon tortuosum var. glabrifolium

Aconogonon tortuosum var. glabrifolium, better known as Persicaria kahil, is a rare knotweed full of qualities, both robust, hardy and floriferous, with rapid growth, perfect in a natural or wild garden. It forms a good ground cover with shiny green foliage that turns rusty brown in winter. It establishes itself vigorously, producing countless short spikes of small white flowers in summer. It will thrive in ordinary garden soil, in sun or partial shade. It integrates well into a low-maintenance wild or naturalistic garden, like Solomon's seals or bearded irises.

The Aconogonon tortuosum var. glabrifolium is part of the Persicaria or Polygonum family, which has changed names many times and belongs to the Polygonaceae family. The botanical species tortuosum is native to Asia, particularly Siberia, the Himalayas, Pakistan, and Nepal. It is an entirely deciduous rhizomatous perennial plant in winter. It forms a clump about 80 cm (32in) tall when in flower and spreads quite rapidly, depending on the richness of the soil: it can form impressive clumps after several years. But the subspecies glabrifolium is a low-growing ground cover, not exceeding 30 to 50 cm (12 to 20in) in height, with a very long summer flowering period that smells of wildflower honey, especially when the sun comes out after rain, from June to September. Many short spikes, 5 cm (2in) long, composed of numerous small pure white honey-scented flowers with prominent stamens and formed by five tepals, emerge at the ends of green leafy stems. The leaves, carried by sturdy stems, are lanceolate and have a beautiful, shiny green colour that enhances other flowering plants. They measure about 3 to 5 cm (1 to 2in) long and have a rough, thick texture.

Very accommodating and perfectly robust, this knotweed fits well in wild environments, requiring little space and maintenance. It can be planted at the base of trees or shrubs as it appreciates root competition, along with perennial geraniums, Solomon's seals, meadowsweets, meadow rues, or other comfreys, in areas of the garden that are a bit neglected, or even in rockeries to form borders or to adorn a pot. It enjoys both sun and partial shade and tolerates occasional drought. It likes rich and deep, fresh soil and cool and semi-shaded woodland areas where it can serve as a worry-free ground cover.