seaside brookweed

It is a small perennial, growing to around 35 cm (13.8 inches) high. Its inflorescence is a raceme, with small white flowers on long stalks. Its corollas have five lobes. It can produce flowers throughout the growing season, from spring to fall. Its fruits are capsules that are green and globose.

Samolus valerandi is widely distributed across western and Mediterranean Europe, north Africa, Asia and Australia, Central and South America including Cuba, and Japan.

The plant's leaves, when cut and agitated in water, produce a lather, for which reason in Palestine it has been used by the local Arab population, in former times, to launder clothes and was called by them sabūn 'arab (= Arab soap).

The plant can be grown in ponds, bog gardens, and damp areas in the garden. S. valerandi prefers light (sandy), medium (loamy), and heavy (clay) soils, preferably neutral or basic (alkaline) soils. It can tolerate both shade and a bright, sunny position. It requires moist or wet soil and can even grow in water. The plant can tolerate maritime exposure and is self-fertile. S. valerandi is sometimes grown in aquariums, although they seem to last only a limited time when grown fully submersed.

Uses. The plant's leaves, when cut and agitated in water, produce a lather, for which reason in Palestine it has been used by the local Arab population, in former times, to launder clothes and was called by them sabūn 'arab (= Arab soap).