Japanese honeysuckle

Japanese honeysuckle: how do you recognise it?

Habit

Semi-evergreen, vigorously twining climber of 6–10 m; without support it forms a dense, creeping mat over the ground and through shrubs.

Leaf

Opposite, oval to oblong, 3–8 cm, untoothed and softly hairy; sometimes lobed on young shoots. Stays on the plant in mild winters.

Stems

Hairy, twining stems that become woody; old stems with flaking bark.

Flower

Two-lipped tubular flowers (3–4 cm), white at first and then yellow, in pairs in the leaf axils, June–October; sweetly scented.

Fruit

Glossy black berries in pairs, in autumn; mildly poisonous.

Difference from common honeysuckle

Common honeysuckle is deciduous, bears its flowers in whorls at the shoot tips and has red berries.

Difference from perfoliate honeysuckle

In perfoliate honeysuckle the top leaf pairs are fused into a dish; it flowers in May–June and has orange-red berries.

Flowering: June–September · Pruning: March–April and July–August

Identify by feature: Black berries · Twining climbers

Looks like it, but isn’t

• Common honeysuckle Lonicera periclymenum: deciduous, with the flowers in whorls at the shoot tips and red berries. Difference from common honeysuckle
• Perfoliate honeysuckle Lonicera caprifolium: top leaf pairs fused into a dish, flowering in May–June and orange-red berries. Difference from perfoliate honeysuckle

Why grow it?

• Keeps its leaves in mild winters: a green screen, even in winter.
• Flowers for a long time, from June to October, with sweetly scented flowers.
• Grows fast and quickly covers a fence, screen or bank.
• Bees, bumblebees and moths visit the flowers; birds nest in the dense stems.

Japanese honeysuckle: where does it grow best?

• Sun to partial shade; it flowers most freely in sun.
• Any soil that is not too wet; it is not fussy.
• It twines and needs wires, mesh, a fence or a sturdy pergola. It does not damage a wall, but it quickly grows into gutters, under roof tiles and through shutters: keep it away from them.
• Don’t let it grow into trees or shrubs: it constricts young trunks and can smother shrubs under a dense mat. Don’t plant it near a woodland edge, hedgerow or nature area, where birds spread the seeds further.

Light

Sun or partial shade

Legal basis

Any garden soil

Moisture

Normal

Size

8 m tall, 3 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• English lavender: A fragrant small shrub for the sunny foot of the fence; together they flower all summer for bees and bumblebees.
• Rosemary: An evergreen, aromatic shrub for the same sunny spot: a green corner, even in winter.
• Common lilac: Flowers and scents the garden in April–May, before the honeysuckle starts: scent from spring to autumn.

Good and bad companions

Goes well with

• Can climb into old, large trees: english oak, scots pine, sycamore, large-leaved lime

Japanese honeysuckle: when and how to plant it?

1. Plant in autumn or spring, from a pot.
2. Plant 30–40 cm from the fence or wall and guide the shoots to the support with a cane.
3. Choose a spot you can get all the way round to keep it in check, such as a fence between lawn and patio, and not next to a hedge or thicket.
4. For a fragrant honeysuckle without the risk of it running wild, choose the native common honeysuckle, or the less vigorous perfoliate honeysuckle.

Care

Watering

In dry spells during the first year; rarely needed after that.

Feeding

Not needed: it grows vigorously enough as it is.

Keeping it in check

In summer, cut away shoots heading for shrubs, trees, the gutter or the neighbours, and pull up creeping stems that are rooting.

Clippings

Put stems and rooted pieces in the green waste bin or on a closed compost heap, never in the wild or at a woodland edge.

Tip: Keep a half-metre strip around the plant clear, with lawn or paving: that way you spot creeping stems straight away and can cut or mow them off before they root.

Japanese honeysuckle: when to prune it?

Pruning months: March–April and July–August.

When: In March–April; in summer (July–August) as often as needed to keep it in check.

How:

• It flowers on new shoots: cut back firmly in March–April and remove old, bare stems.
• In July–August, cut back overlong shoots and keep gutters, windows and neighbouring shrubs clear.
• An overgrown plant can be cut back close to the ground in spring; it will reshoot vigorously.

Caution: First check that no birds are nesting in the dense stems. Don’t leave cut stems lying on moist soil: they can take root there.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Layering

Creeping shoots root by themselves where they touch the ground: dig up a rooted shoot and replant it.

Cuttings

10–15 cm cuttings root easily in a small pot in summer.

Japanese honeysuckle: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Hardy. In mild winters it keeps most of its leaves; in severe winters they drop and it comes back into leaf in spring.
• Winter is when you can best see where stems have crept into the gutter, under tiles or into shrubs.

Diseases and pests

• Rampant growth: Smothers shrubs, hedges and young trees and creeps under roof tiles. Cut it back every summer and pull up creeping stems.
• Escaping: Seedlings or stray shoots outside the garden. Pull them up young, roots and all; dig out larger plants, or cut them to the ground again and again until they are exhausted.
• Aphids: Aphids on the shoot tips, especially in dry weather. Spray with water; ladybirds and tits do the rest.
• Powdery mildew: White, powdery coating on the leaves in dry spots. Water in dry spells and cut off affected shoots.

Through the year

• March: Spring pruning: cut back firmly and remove old stems; planting.
• April: Last spring pruning; guide new shoots to the support.
• June: Flowering begins: white and yellow flowers at the same time.
• July: Summer pruning: shorten overlong shoots and clear the gutters.
• August: Summer pruning; water in dry spells.
• October: Last flowers; black berries.
• November: Pull up creeping stems and seedlings around the plant.

What can you use it for?

Garden and landscape

Semi-evergreen, fragrant climber for a fence or screen, also as ground cover on a bank.

For wildlife

Bees, bumblebees and moths visit the flowers; the dense stems are nesting sites for birds.

Caution: Grows very vigorously and is an invasive pest in North America: don’t dump clippings in the wild. The berries are mildly poisonous.

Did you know?

• In Chinese it is called ‘gold and silver flower’, because white and yellow flowers hang on it at the same time. In North America it is a notorious invasive species.
• It was introduced to North America in the early 19th century as an ornamental and later also planted against erosion; today it overruns woodland edges and young forests across much of the east of the continent.
• The dried flower buds are a well-known remedy in traditional Chinese medicine.