Japanese Honeysuckle (Lonicera japonica) - Invasive Plant Guide | Sycamore
White and yellow flowers on the same runner in May. They open white and age to yellow. The stems running flat across the leaf litter, rooting as they go, are the other half of the ID.Photo: iNaturalist (CC0), Susan Christman WilliamsPlain oval leaves in facing pairs, with the paired white trumpets between them. The top pair is never fused, unlike native coral honeysuckle’s.Photo: iNaturalist (CC0), mefisher
🔴 Invasive - Remove
Japanese Honeysuckle
Lonicera japonica
This is an invasive species that harms native ecosystems. It should be removed when found to protect local plant and wildlife habitats.
Description
A twining, semi-evergreen vine with paired oval leaves and sweetly scented white flowers that fade to yellow. It carpets the ground and climbs shrubs and small trees, staying green well into winter after natives have dropped their leaves.
Where you'll find it
Running over the ground in woods and along edges, rooting at every node it touches.
Twining up saplings, fences and shrubs, often leaving a spiral groove in the stem it strangled.
Green in December when the natives around it are bare, which is the giveaway in winter.
Background
Native to: East Asia (Japan, Korea, China)
Brought to Long Island in 1806 as an ornamental and later planted widely for erosion control and as deer browse. It escaped everywhere it was planted and is now one of the most common vines in Mid-Atlantic woods.
Ecological impact
Smothers ground-layer plants and girdles saplings as its stems tighten around them. Because it keeps its leaves into winter it shades out spring wildflowers before they emerge, and birds spread its black berries into every hedgerow.
How to identify
The leaf
Plain oval leaves in facing pairs along the stem.
Colour and texture: Plain mid-green, smooth-edged, semi-evergreen. Young stems are reddish and hairy; old vines have shaggy tan bark.
Leaves: opposite pairs, oval, 1–3 inches, usually smooth-edged (young leaves near the base can be lobed). Semi-evergreen — still green in December.
Stems: young stems are reddish and hairy; older vines have shaggy, peeling tan bark. Stems twine and root wherever they touch the ground.
Flowers: paired, tubular, white ageing to yellow, strongly fragrant, May–June.
Berries: small and black, in autumn.
Seedheads & fruit
Berries September–November.
Small, shiny black berries in pairs where the leaves join the stem.
Why it matters: Black berries in pairs separate it from native coral honeysuckle, whose berries are red. It is birds eating those berries that put it in every hedgerow.
Preferred removal method
Pull low, slow, and whole
Anything with a taproot or shallow roots: garlic mustard, mile-a-minute, seedlings, honeysuckle runners.
1Grip the stem at the very bottom, where it meets the soil, not by the leaves.
2Pull straight up, slowly. Rock it first if the ground is hard, or come back after rain.
3A snapped stem with the root still in the ground is not a removal, because that root re-sprouts. Check every plant you pull.
Avoid: Do not yank. Speed is what snaps the stem at the root collar and leaves the half that matters behind.
Follow the runner to every knuckle
A plant that travels sideways and roots where it touches: kudzu, Japanese honeysuckle, ivy runners.
1
Disposal
It can stay on site. Cut vine can stay, but keep it off the soil: this is one of the ones that roots wherever a node touches dirt, so a pile left flat re-roots into a mat.
Don't confuse with a lookalike
🔎Native Coral Honeysuckle vs Japanese Honeysuckle
Coral honeysuckle is a native vine that hummingbirds depend on, and it is regularly pulled by mistake because "honeysuckle" reads as invasive. Two checks, neither of which needs a flower.
Find a runner and follow it along the ground in both directions.
2At every swollen knuckle that has rooted, cut or dig just below the surface. Each knuckle is a whole plant in waiting.
3Work outward from the edge of the patch toward the middle, so you always know which ground you have cleared.
Cut a window in the vine
A woody vine climbing a tree. This is the safe way to free a tree: you never pull a vine down out of a canopy.
1Cut every strand at ankle height, all the way round the trunk.
2Cut again as high as you can comfortably reach. No ladders, no pulling on branches.
3Pull out the band between the two cuts so the vine cannot rejoin, and leave everything above it to die in place. It drops on its own over a season.
Avoid: Do not haul the vine down. It is tangled into the branches, and pulling brings down deadwood on top of you.
Grab from the kit, in this order
Before the first cut: Pull slowly and the runners come up in long strands; every rooted node you leave behind re-sprouts.
Seedlings and small plants: hand-pull. Young plants (under about two years) come up whole if you pull slowly, and the runners follow in long strands. Get the rooted nodes or they re-sprout.
Established vines: do not try to rip out big roots — they fragment and every piece re-sprouts. Cut at the base and again at shoulder height, pull what comes easily, and note the patch for the coordinator; the extension services' advice for large stands is a fall herbicide treatment, when it is still green and natives are dormant.
Best window: late autumn through early spring. It is still green while the natives around it are bare, so it is easy to see and you are not trampling wildflowers.
Cut or pull; trace every runner back to its root.
Bag anything carrying berries.
Expect to return — re-sprouts from missed roots are normal.
Japanese Honeysuckle
Lonicera japonica
Invasive: remove
What coral (trumpet) honeysuckle looks like
The check that settles it: the top pair of leaves is fused into one disc that the stem grows straight through, under red-orange trumpets.Photo: iNaturalist (CC0), Karen McCabeRed to orange trumpets in whorls at the shoot tips, yellow inside and almost scentless. Japanese honeysuckle is white ageing to yellow, in pairs, and strongly fragrant.Photo: iNaturalist (CC-BY), Joshua Liverman
The top pair of leaves
Coral (Trumpet) Honeysuckle
Fused into a single disc that the stem grows straight through, like a collar. Look at the last few inches below the flower head.
Coral honeysuckle: the stem grows through one fused leaf disc.
Japanese Honeysuckle
Never fused. Every pair stays as two separate leaves the whole way up.
Leaf colour
Coral (Trumpet) Honeysuckle
Blue-green and waxy, smooth on both sides.
Japanese Honeysuckle
Plain mid-green; young leaves near the base are sometimes lobed, and young stems are reddish and hairy.
Flowers
Coral (Trumpet) Honeysuckle
Red to orange trumpets in whorls at the tips of the shoots, yellow inside, and almost scentless.
Coral honeysuckle flowers are red, and hummingbirds depend on them.
Japanese Honeysuckle
Paired white trumpets that age to yellow, down the length of the stem, and powerfully fragrant.
Berries
Coral (Trumpet) Honeysuckle
Red.
Japanese Honeysuckle
Black.
What it does to its host
Coral (Trumpet) Honeysuckle
Twines politely up a shrub or trellis and stays where it is put. It does not run along the ground.
Japanese Honeysuckle
Carpets the ground and roots at every node, then spirals tight enough around saplings to leave a corkscrew groove and girdle them.
When in doubt, leave the plant and ask a site lead before removing it.
