Persicaria minor aka Pygmy Smartweed

Persicaria minor is an annual in the knotweed family, Polygonaceae. Its common names include small water pepper and y dinboeth fach. The RHS lists Polygonum minus as a synonym. This older name appears in the Plants For A Future account. Its native range spans Eurasia and reaches the northwest Pacific. The RHS confirms that it is native to Britain and Ireland. Kew places it in the temperate climate zone.

This small plant grows to about 1 foot [0.3 metres] tall. It flowers from August to September, according to Plants For A Future. Each flower has both male and female organs. Insects pollinate the flowers. The supplied species account gives no details of flower colour. It also gives no species-level description of leaves or stems. The RHS describes these features only for the wider genus. Those details do not establish this species' exact form.

In the wild, it grows in wet, marshy ground. It also occurs beside lakes and ponds. These habitats fit its need for moist or wet soil. Plants For A Future lists it for use in bog gardens. It accepts sandy soil, loam, and clay. It also tolerates mildly acid, neutral, and mildly alkaline conditions. Ordinary garden soil can support it, provided the site meets its moisture needs. The account favours soil that holds moisture without being too fertile. Plants can grow in sun or partial shade.

Plants For A Future recommends raising it from seed in spring. Sow the seed in a cold frame. The account reports that seeds germinate readily. Move seedlings into separate pots once large enough to handle. Plant them outside in summer once they reach a suitable size. The source reports that rabbits tend to leave this plant alone. It does not identify any species-specific pests or diseases. No hardiness rating appears in the supplied evidence.

The leaves and seeds have recorded food uses. People eat the leaves raw, cooked, or in curries. Seeds can also be eaten raw or cooked. Their small size makes them awkward to use. Plants For A Future gives edibility one point out of five. It lists no known medicinal or other uses. Its safety warning concerns related plants, not confirmed effects in this species. The supplied evidence therefore does not establish a species-specific toxicity rating.