Common Name: Japanese Honeysuckle

General Information

Lonicera japonica is an evergreen climbing shrub with stems 5 metres or more long that scramble over the ground and into the surrounding vegetation, supporting themselves by twining around other plants.
The plant is commonly used in Chinese herbalism. It is widely cultivated as an ornamental from the temperate zone to the tropics and is also used as a ground cover[].
A rampantly growing plant, climbing by twining around other plants[, ] This species has the potential to become a rampant weed, it has escaped from cultivation in N. America where it can outcompete native species[].

Known Hazards

The leaves contain saponins[]. Saponins are quite toxic but are poorly absorbed by the human body and so most pass through without harm. They can be found in many common foods such as some beans. Thorough cooking, and perhaps changing the cooking water once, will normally remove most of the saponins. Saponins are much more toxic to some creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish[].

Botanical References

, ,

Range

E. Asia - China, Japan, Korea. Locally naturalized in Britain[]

Habitat

Thickets in hills and mountains all over Japan[]. Woods in the mountains and lowlands of Korea[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Climber
Height	5.00 m
Growth Rate	Fast
Pollinators	Moths
Cultivation Status	Wild

Cultivation Details

Lonicera japonica is a plant mainly of the temperate zone, though it has also been cultivated in the tropics. When dormant, plants are hardy to about -20°c[]. The foliage can be damaged in severe wind-chill conditions but the plant usually recovers in the spring[]. Fruit is only formed after a hot summer[].
Prefers a good moist soil with its roots in the shade and its top climbing into the light[]. Succeeds in any soil in part shade[]. Established plants are drought tolerant[]. They succeed in dry shade, the cultivar 'Halliana' is especially recommended for such a situation[].
A rampantly growing plant[], it climbs by twining around other plants[] and makes an excellent screen for a north or east facing fence or an unsightly object[].
The plant has powerfully scented flowers. The white-flowered cultivar 'Halliana' has a pronounced lemon-like perfume[].
There are several named varieties, developed for their ornamental value[, ].

Edible Uses

Leaves - cooked. The parboiled leaves are used as a vegetable[]. Some caution is advised, see notes above on toxicity.

Flowers - sucked for their sweet nectar[], used as a vegetable or made into a syrup and puddings[].

A tea is made from the leaves, buds and flowers[, ].

Medicinal

The stems and flower buds are alterative, antibacterial, anti-inflammatory, antispasmodic, depurative, diuretic, febrifuge[, , , , ]. The plant is also used to reduce blood pressure[, , ].
The leaf-bearing stem is antibacterial and antiallergic. It is recommended in the treatment of boils, impetigo, urticaria, allergic rhinitis, fever, malaria, erythema, measles, diarrhoea, dysentery, syphilis, rheumatism and lichen tropicus[].
The stems are used internally in the treatment of acute rheumatoid arthritis, mumps and hepatitis[].
The stems are harvested in the autumn and winter, and are dried for later use[].

The stems and flowers are used together as an infusion in the treatment of upper respiratory tract infections (including pneumonia) and dysentery[].

An infusion of the flower buds is used in the treatment of a wide range of ailments including syphilitic skin diseases and tumours, bacterial dysentery, colds, enteritis, pain, swellings etc[, , , , , ]. Experimentally, the flower extracts have been shown to lower blood cholesterol levels and are antibacterial, antiviral and tuberculostatic[, ]. Externally, the flowers are applied as a wash to skin inflammations, infectious rashes and sores[]. The flowers are harvested in early morning before they open and are dried for later use[]. The plant has a similar action to Forsythia suspensa and is usually used in combination with that species to achieve a stronger action[].

This plant has become a serious weed in many areas of N. America, it might have the potential to be utilized for proven medical purposes[].

Agroforestry Uses:

A very vigorous climbing plant, it makes a good dense ground cover plant where it has the space to run over the ground but it will swamp smaller plants[, ]. The sub-species L. japonica repens is especially used for this purpose on the continent[]. The cultivar 'Halliana' has also been recommended[, ]. This cultivar should be clipped back severely in the spring if it gets untidy, it responds well to such conditions[]. Plants should be spaced about 1 metre apart each way[].
The plant makes an excellent screenwhen grown over a north or east facing fence or an unsightly object[].

Other Uses

The plant is said to be insecticidal[].

The stems have been used in making baskets[].

Propagation

Seed - best sown as soon as it is ripe in a cold frame. Stored seed requires 2 months cold stratification[] and should be sown as soon as possible 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 at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Cuttings of half-ripe wood, 7 - 10cm with or without a heel, mid summer in a frame. Good percentage[].
Cuttings of mature wood of the current season's growth, 15 - 20cm with or without a heel, late autumn in a cold frame. Good percentage[].
Layering in autumn[].