Kozo
Broussonetia kazinoki

Family: Moraceae

What it is like

Broussonetia kazinoki is a deciduous Tree growing to 4.5 m (14ft 9in). See above for USDA hardiness. It is hardy to UK zone 7 and is not frost tender. It is in flower in August, and the seeds ripen in September. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant). The plant is not self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil. It can tolerate atmospheric pollution.

Height (m): 4.5

Where it is found

Forest margins, low mountains and near houses.

E. Asia - C. and S. Japan, Korea.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 3

Fruit - raw. A sweet taste. The fruit comprises a ball about 1cm in diameter with small edible fruits protruding - there is not much edible flesh but it has a lovely flavour. Prolonged ingestion of the fruit is said to weaken the bones. Leaves - cooked and used as a vegetable. Flowers. No more details.

Medicine

Rating: 1

The fruit is used as a tonic to increase vision and sexual potency.

Tonic: Improves general health. Slower acting than a stimulant, it brings steady improvement.

Other

Rating: 1

A fibre from the bark is used in making paper, cloth, rope etc. It is inferior to B. papyrifera.

Fibre: Used for making cloth, rope, paper etc.

How it is grown

Easily cultivated in a warm sunny position in any soil of reasonable quality, thriving on poor sandy or gravelly soils. Tolerates atmospheric pollution. The young growth in spring, even on mature plants, is frost-tender and so it is best to grow the plants in a position sheltered from the early morning sun. Often cultivated in Japan for the fibre in its bark, the tree is coppiced annually for this purpose. Some plants are monoecious whilst others are dioecious. Male and female plants must usually be grown if seed is required.

Propagating it: Seed - no pre-treatment is required. Sown in the autumn or spring in a greenhouse, germination usually takes place within 1 - 3 months at 15°c. When large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter, planting them out into their permanent positions in late spring or early summer, after the last expected frosts. Cuttings of half-ripe wood, 8 - 12cm long with a heel, July/August in a frame. High percentage. Cuttings of mature wood of the current season's growth, November in a frame. Root cuttings in winter. Layering in spring.

Best place to grow: Woodland Garden Sunny Edge; Dappled Shade;

Habit: Tree

Hardiness: 6-9

Growth:

Soil: Light (sandy), medium, heavy (clay)

Shade: No shade

Moisture: Dry, moist

Things to keep in mind

Its other names

Local names

Synonyms

B. kaempferi. non Sieb.&Zucc. B. monoica. B. sieboldii.