Persicaria capitata aka Pink Headed Knotweed

Persicaria capitata is in the knotweed family. The family's name is Polygonaceae. Gardeners call it pink knotweed or pink bobbles. Its old name is Polygonum capitatum. It comes from the Indian subcontinent, southern China, and Indo-China. It is not native to Britain or Ireland. In the wild, it grows on mountain slopes. It also grows in shaded parts of valleys. Records place it at heights of 1,970–11,480 feet [600–3,500 metres].

This plant keeps its leaves year-round and lives for several years. Its stems branch to form a low mat. It grows about 0.5 feet [0.15 metres] tall. Kew also calls it a subshrub. Its stems creep over the ground and turn woody at their base. Roots grow at leaf nodes, where leaves join the stems. These roots help the mat spread. This growth makes it useful as a low garden cover. The sources give no full-grown width for garden plants. They give no details on this species' leaf shape, flowers, or fruit. Insects pollinate its flowers. The sources do not say when it blooms.

This plant can grow in poor soil and harsh sites. Records show it rooting among rocks and in pavement cracks. It grows in shade in the wild. Its light needs in gardens are still unclear. The evidence gives no firm guide to watering or soil pH. Cold limits its use outdoors as a long-lived plant. Plants at full rest can bear brief spells around −5 to −8°C. This does not show they can bear long spells of frost. The sources give no formal hardiness zone.

Its spread can cause problems in gardens. Plants spread with ease in gardens and sometimes escape. It now grows wild across warm temperate and tropical regions. Hawaii lists it as invasive. Roots along its stems help it form dense cover. The evidence names no specific pests or diseases. The sources flag spread where it is not wanted, rather than pest damage.

People also gather wild plants for use in folk medicine. In China, people have long used it to treat urinary disorders. Reports also describe plant juice used for stomach complaints. People put plant paste on boils and wounds. These reports record uses as medicine. They do not guide home treatment. The source lists no known hazards, but that does not prove safety. It gives no confirmed use of this species as food.