Listed as a schedule 9 species under Articles 15 & 15A of the Wildlife Order (Northern Ireland) 1985 (Article 15A not yet enacted).
First reported in the wild
Invasive species - risk of Medium Impact
Introduction pathways - 1
Escape from Confinement
Introduction pathways subclass - 1
NAPRA Ireland risk assessed
Deciduous semi evergreen climbing shrub generally 4-6 (up to 10m) tall; ovate to oblong, 3-8cm length dark green leaves; white flowers in April to October (Booy et al., 2015).
Most of the studies on the ecology and effects of Japanese honeysuckle are from the United States. There it has been shown to have more detrimental effects than a native vine on Liquidambar styraciflua (American sweet gum) (Dillenberg et al., 1993) and is considered a pest of forestry for loblolly and shortleaf pines (Shelton & Cain, 2004). At a community level findings suggest that the declines in species richness associated with L. japonica invasion is caused by decreasing local colonization rates (Yurkonis & Meiners, 2004) and increasing local extinction rates (Yurkonis et al., 2005). Additionally high-performance liquid chromatography extracts from leaf tissue of Japanese honeysuckle has suggested the presence of five compounds, identified as possible allelochemicals (chemicals that prevent the growth of other plants) (Skulman et al., 2004). L. japonica has also been shown to demonstrate a strong compensatory response to herbivory (Schierenbeck et al., 1994) and this is conjunction with the lack of specialist herbivores in its invaded range may give it a competitive advantage over native species.
Woodland, forest and other wooded land; Heath, scrubland & tundra; Inland unvegetated or sparsely vegetated habitats; Constructed, industrial or other artificial habitats
Shows a number of reproductive characteristics associated with successful invaders: can reproduce in low sunlight, =2%, (Schierenbeck, 2004); extended flowering period from April to October (Booy et al., 2015); can reproduce vegetatively (Schierenbeck, 2004); and animal dispersed seeds allowing it to be widely dispersed (Schierenbeck, 2004). However it may require disturbance to invade new areas as seeds have low viability (1-3% germination rates) after 3 years (Shelton & Cain, 2002)., and in parts of its invasive range the lack of pollination is a limiting factor in fruiting (Larson et al., 2002).
Pathway and vector description
Popular garden plant and cultivar, with a long history of cultivation having been originally brought from China to Britain by William Kerr in 1806 and was introduced into the United States in 1842 (Schierenbeck, 2004). First record from the wild in Ireland dates from 1997 though it is likely to have been present in gardens prior to that (Reynolds, 2002). Due to the long history of cultivation, different cultivars may show differences in their impacts and ability to spread. Lack of pollination is thought to be the limiting factor in fruiting (Larson et al., 2004), suggesting there may be an extended lag phase in the invasion of this plant while local pollinators adapt to using it.
Mechanism of impact
Competition, Poisoning/Toxicity, Bio-fouling
Found in woodlands, hedgerows, cliffs, roadsides and on waste ground (Preston et al., 2004; Reynolds, 2002), though likely to be able to survive in a wide range of environments (Schierenbeck, 2004). In the United States, while it prefers soils of pH 6.1 to 7.9, it has been found in areas with soil pHs ranging from 4-8 and can survival and reproduction in =2% sunlight (Schierenbeck, 2004).
Established - Rare/Localised, possibly under recorded. Distribution may be an artefact of recording effort.
Native to hills of Japan, Korea, and eastern China (Ohwi, 1965 in Schierenbeck, 2004).
Date of first record category
Fifty year date category
Records submitted to Data Centre in 2022
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How can you help
Report any sightings to the National Biodiversity Data Centre. Do not plant in the wild or in gardens where it may escape or seed into the wild.
Reynolds, S.C.P. (2002) A catalogue of alien plants in Ireland. National Botanic Gardens. Glasnevin, Dublin. Preston, C.D., Pearman, D. A. & Dines, T. D. (2002). New atlas of the British and Irish flora. An atlas of the vascular plants of Britain, Ireland, the Isle of Man and the Channel Islands, Oxford University Press. Stace, C. (1997). New Flora of the British Isles 2nd Edition. Cambridge University Press, Cambridge. Skulman, B. W., Mattice, J. D., Cain, M. D., & Gbur, E. E. (2004). Evidence for allelopathic interference of Japanese honeysuckle (Lonicera japonica) to loblolly and shortleaf pine regeneration. Weed Science, 52(3), 433-439. Ohwi, J. 1965. Flora of Japan. Washington, DC: Smithsonian Institution. Shelton, M. G., & Cain, M. D. (2002). Potential carry-over of seeds from 11 common shrub and vine competitors of loblolly and shortleaf pines. Canadian Journal of Forest Research, 32(3), 412-419. Larson, K. C., Fowler, S. P., & Walker, J. C. (2002). Lack of pollinators limits fruit set in the exotic Lonicera japonica. The American midland naturalist, 148(1), 54-60. Dillenburg, L. R., Whigham, D. F., Teramura, A. H., & Forseth, I. N. (1993). Effects of below-and aboveground competition from the vines Lonicera japonica and Parthenocissus quinquefolia on the growth of the tree host Liquidambar styraciflua. Oecologia, 93(1), 48-54. Yurkonis, K. A., Meiners, S. J., & Wachholder, B. E. (2005). Invasion impacts diversity through altered community dynamics. Journal of ecology, 93(6), 1053-1061. Schierenbeck, K. A. (2004). Japanese honeysuckle (Lonicera japonica) as an invasive species; history, ecology, and context. Critical reviews in plant sciences, 23(5), 391-400. Schierenbeck, K. A., Mack, R. N., & Sharitz, R. R. (1994). Effects of herbivory on growth and biomass allocation in native and introduced species of Lonicera. Ecology, 1661-1672.