Japanese Honeysuckle (Lonicera japonica)

Photo: (c) Mokkie CC BY 3.0 License

Family: Caprifoliaceae

Growth Habit: A woody climber or scrambler with stems growing up to 10 m long. Leaves are oblong or egg-shaped, 2.5-8 cm long and 1-4 cm wide, usually hairless, with entire margins and pointed or rounded tips and paired along the stem. The younger stems are greenish or reddish in colour and usually have a dense covering of tiny hairs. Older stems may become quite thick and woody, developing a greyish-coloured bark as they age.

Type of Plant: A climbing or scrambling plant up to 8 m high.

Photo (c) Qwert1234 CC-BY-SA-03 license

Flowers: Profuse fragrant and nectar filled flowers are 405 cm long. Their petals are fused into a tube (i.e. corolla) for part of their length and then separate into two ‘lips’. The wider upper lip having four small lobes and the lower lip with a single lobe. Flowers are initially white or pinkish tinged, but turn cream or yellowish as they age.

Fruit/Seed: Shiny egg-shaped black berries (5-10 mm long) with a few seeds in each.

Dispersal: Japanese Honeysuckle occasionally reproduces by seed, but more commonly it spreads vegetatively via its creeping stems which produce roots at their joints (i.e. via stolons). Seeds are dispersed by birds and other animals that eat the fruit, while the seeds and stem segments are also spread by water, in dumped garden waste, by slashers and in contaminated soil.

Distribution: This species has mainly become naturalised in or near rainforests and other closed forests, particularly those close to habitation. It also grows in riparian areas, distrubed sites and waste areas

Status: Environmental Weed, especially in moist conservation areas.

Weed Impact:

  • Smothers and out-competes native vegetation and prevents the regeneration of native species.
  • Japanese honeysuckle is toxic to humans, causing discomfort and irritation but is not life threatening. The berries and leaves are poisonous if ingested, causing gastro-intestinal irritation. It is also a skin irritant causing rashes on contact with the plant.

Control Methods:

  • Plant alternative species such as Clematis, Hibbertia scandens, and Jasminum azoricum.
  • Do not dump garden waste.
  • Cut / Stump with Glyphosate.
  • Spot or foliar spray with Metsulfuron-methyl

N.B. Always check the herbicide label before use.