Helwingia japonica - Japanese helwingia

Helwingia japonica, the Japanese helwingia, is a small deciduous bush, sought after for its "epiphyllous" inflorescences, borne directly on the midrib of the leaves. In the garden, it can be used in shaded borders, at the foot of large deciduous trees, or in a large pot on a sheltered terrace. This female specimen will bear fruit in late summer if a male plant is present nearby. Not very hardy, it will thrive in partial shade, in a light, humus-bearing and moist soil.

This species belongs to the Helwingiaceae family and the Helwingia genus. The genus was dedicated to the Prussian botanist Georg Andreas Helwing (1666-1748); the epithet japonica refers to part of its native range. H. japonica is native to the cool forests and moist ravines of East Asia (China, Japan, Korea, Bhutan, Myanmar), from lowlands up to the montane zones.

The shrub produces several stems from its crown and has a bushy habit. It is slightly suckering. Its dimensions reach 1 m to 1.50 m in height and spread in 5 to 10 years in open ground. In a pot, it will measure 0.80 m to 1.20 m, depending on the container volume and care. The smooth shoots are green to brownish. The alternate, elliptical to ovate leaves measure 6 to 12 cm long and are finely toothed. Bright green in season, they turn yellow in autumn before falling.
The plant is dioecious: male and female flowers are borne on separate individuals. The (3 to 5 mm), greenish to greenish-purple flowers open in April-May and are grouped in small umbels at the top of the midrib of the leaf. On the female plant, 1 to 3 flowers are observed per leaf. Fertilisation, carried out by small insects, allows the formation of small drupes, first reddish then black, from August to October, visible above the leaf. 
The bush is hardy down to -10°C at its limit; it gives the best results in mild and humid climates. The plant is generally not very susceptible to pests and diseases.

Plant Japanese helwingia in a cool woodland setting: at the edge of a small tree (large Japanese maples, flowering dogwoods), along a path or near a water feature, where its flowers and then its berries above the leaves will intrigue passersby. Also, pair it with modestly sized bushes like Skimmias or sacred bamboos (Nandina). The variegated cultivars of Fatsia japonica or an Aucuba japonica ‘Rozannie’ will form a beautiful backdrop, even in winter.
In cold regions, it is possible to grow it in a large pot, allowing it to be overwintered protected from frost.