Japanese Hop
Humulus japonicus

Family: Cannabidaceae

What it is like

Humulus japonicus is a PERENNIAL CLIMBER growing to 6 m (19ft 8in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 5 and is not frost tender. It is in flower from July to August, and the seeds ripen from September to October. The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). and is pollinated by Wind. The plant is not self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 6

Where it is found

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

E. Asia - China, Japan, Korea.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 2

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

Oil: Oil

Medicine

Rating: 1

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

Diuretic: Acts on the kidneys, promoting the flow of urine.

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

Urinary: Treats urinary problems, including urinary tract infection (UTI).

Other

Rating: 0

The seed oil is used to make soap.

Oil: Vegetable oils have many uses, as lubricants, lighting, soap and paint making, waterproofing etc. This does not include the edible oils unless they are also mentioned as having other uses.

Scented Plants: Plants noted for their scent

How it is grown

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. Dioecious. Male and female plants must be grown if seed is required.

Propagating it: 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 March. 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.

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

Habit: Perennial Climber

Hardiness: 4-8

Growth: Fast

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

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

Its other names

Local names

Synonyms

H. scandens. (Louriero.)Merrill.