Ardisia japonica, known as marlberry, is a species of plant in the primrose family native to eastern Asia, in eastern China, Japan and Korea.
It is a low-growing, spreading very quickly evergreen shrub 20âÂÂ40 cm tall. The leaves are opposite or in whorls, ovate, 4âÂÂ7 cm long and 1.5âÂÂ4 cm broad, with a sharply serrated margin and an acute apex. The fruit is a drupe 5âÂÂ6 mm diameter, red maturing dark purple-black in early winter. The flowers are 4âÂÂ10 mm diameter, with five (rarely six) white to pale pink petals; they are produced in racemes in late spring. The plant flowers from August to September.
A. japonica grows in dark, damp places in mixed forests and bamboo forests within 1200 metres of sea level.
A number of cultivars have been selected for growing as ornamental plants, including 'Hakuokan' and 'Ito Fukurin' with variegated leaves, 'Hinotsukasa', with pale cream-coloured leaves, and 'Matsu Shima' with pink stems and variegated leaves.
A. japonica is one of the plants used in koten engei, a traditional form of Japanese horticulture. At least a dozen cultivars of the species are grown in this tradition, with varying shapes and coloration of leaves.
The plant is called Jà «ryà  (Ã¥ÂÂ両) in Japanese. Because of the red berries and the word play of its name it is used during Japanese New Year for chabana decoration, normally along winter jasmine.
It is used as a medicinal plant in traditional Chinese medicine, where it is called zÃÂjën niú (), or aidicha (ç®å°è¶) and is considered one of the 50 Fundamental Herbs.
Large doses of the plant as medicine can be toxic to the kidneys.
It has escaped from cultivation and established itself in the wild in the United States, in Gainesville, Florida, and possibly as far as South Carolina and Texas.