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Common Name: Japanese Hop

General Information

Humulus japonicus is a Perennial Climber up to 6.00 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - China, Japan, Korea.

Habitat

Thickets and roadsides in lowland areas all over Japan[]. Forest margins, wastelands and along the sides of streams in China[].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial Climber
Height	6.00 m
Growth Rate	Fast
Pollinators	Wind
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Easily grown in a good garden soil in sun or semi-shade[, ]. Prefers a deep rich loam[]. A fast growing plant, with annual stems of up to 10 metres long being produced[].
Plants rarely survive the winter outdoors in Britain, so are best grown as annuals[]. This report needs confirmation since the plant is also reported as being hardy in zone 5 which would mean that it should succeed outdoors virtually anywhere in Britain[].
A climbing plant, supporting itself by twining around the branches of other plants[].
The bruised leaves are refreshingly aromatic whilst the flowers cast a pleasing scent[].
A dioecious species - both male and female forms must be grown if fruit and seed are required.

Edible Uses

Young leaves and young shoots - cooked[, , ]. Use before the end of May.

Medicinal

The whole plant is diuretic and a genito-urinary tonic[, ].

Other Uses

The seed oil is used to make soap[].

Propagation

Seed - sow spring in a cold frame[]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Division in spring as new growth begins[]. Take the divisions when the new shoots are about 10cm above ground level. Larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring.
Basal cuttings in early spring. Harvest the shoots when they are about 10 - 15cm long with plenty of underground stem. Pot them up into individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer.