Japanese honeysuckle
Botanical Name
Lonicera japonica
Family
Caprifoliaceae (honeysuckle)
Where is it originally from?
Japan
What does it look like?
Vigorous evergreen (semi-evergreen in cold districts) climber with long, tough, wiry stems that twine clockwise, are purplish and hairy when young, and turn woody as they mature. Leaves (3-12 x 2-6 cm) are in opposite pairs on the stems, are shiny dark green (occasionally yellowish) on the top and lighter green underneath, and are wavy-edged to lobed when produced in cold climates, otherwise they are entire. Pairs of 2-lipped, sweetly scented tubular white flowers (2-5 cm long) that age to yellow are produced from September to May, and are followed by egg-shaped, glossy black berries (5-7 mm diameter) in colder parts of NZ, each containing seeds (2mm).
Are there any similar species?
Many similar Lonicera species are cultivated, and hybrids and cultivars of L. japonica. L. pericyclamineum and L. x americana are both found in the wild.
Why is it weedy?
Climbing, smothering habit. Forms dense, long-lived masses. Tolerates moderate-shade, frost, salt, damage, wet or dry, most soils, high to low temperature. Very long stems layer profusely, moderate-fast growth rate. Poor seeder.
How does it spread?
Birds, possibly possums. Roading machinery, dumped vegetation, soil and fill. Roadsides, wasteland, plantation forest, hedges, shelterbelts.
What damage does it do?
Climbs over and smothers most plants from ground to medium canopy. Can cause canopy collapse and subsequent invasion of grasses or ground vines. Provides support for faster growing weedy vines (eg morning glory, moth plant).
Which habitats is it likely to invade?
Forest margins, shrublands, disturbed forest, coastal areas, river systems, wetland margins, fernland, and inshore islands.
What can I do to get rid of it?
1. Cut and paste - Cut the stem/trunk as close to the ground as possible and again above ground (to prevent aerial roots attaching from hanging stems) and cover the entire stump with herbicide as soon as possible after cutting. Apply metsulfuron gel (10g/l strength) or picloram gel (43g/l strength), or a product containing triclopyr + picloram 50ml/L water mixture over the entire cut stump. Dispose of cutaway segments to refuse transfer station or burn.
2. Foliar spray - summer to autumn
Apply Glyphosate (360 g/L active ingredient) herbicide at a rate of 20ml/L to cover entire plant.
OR Apply metsulfuron herbicide at a rate of 0.5g/L using a hand held sprayer/knapsack. Use the recommended adjuvant shown on the label.
OR apply Triclopyr herbicide (600g/L active ingredient) at a rate of 6ml/L to thoroughly wet all parts of plant
OR apply Picloram/triclopyr herbicide (picloram 100g/l and triclopyr 300g/l active ingredient) at a rate of 6ml/L to thoroughly wet all parts of plant.
Note: Overspray will kill other (desirable) broadleaf plants. Picloram and metsulfuron based herbicides have residual activity in the soil which may leach through soil and kill other plants, do not use under and around other (desirable) broadleaf plants. Do not use these herbicides over or near water bodies or wetlands and use only as directed on label.
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and directions for the purchase, use and storage of the product, are followed and adhered to.
What can I do to stop it coming back?
Hard to kill. Stumps resprout, stems layer, but very shy seeder, so sites usually remain clear after treatment. Check for new sprouts 6-monthly until clear. Replant bared areas if seedlings are a problem.
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