Lygodium japonicum | Japanese climbing fern | Raithneach dhreaptha Sheapánach

Pre 2017

2017 - 2020


Legal status

Regulated invasive species of Union concern under the European Regulation on the prevention and management of the introduction and spread of invasive alien species [1143/2014].

Native status


First reported in the wild

Not present in Ireland or Northern Ireland


Invasive species - risk of Medium Impact

Irish status


Introduction pathways - 1

Escape from Confinement

Introduction pathways subclass - 1


Introduction pathways - 2

Transport Contaminant

Introduction pathways subclass - 2

Contaminant nursery material

NAPRA Ireland risk assessed


Species Biology


Lygodium japonicum is a species of rhizomatous (spreads via a network of horizontally spreading appendages) vine that can reach up to 30 m in length (Invasive Species Ireland, 2021). The creeping rhizomes have black to reddish-brown hairs with stripes every 1cm (CABI, 2021). The fronds (long, divided leaf e.g. ferns) are long and are evenly divided along the vines (Global Invasive Species Database, 2021). The rachis (main axis of the leaf) can be hairy or glabrous (hairless) and can be 3-30 m long (CABI, 2021). It is pinnate (structure similar to that of a feather) with short stalks of 3-5 cm (CABI, 2021).


Depending on the climate, Lygodium japonicum can be evergreen, growing and reproducing all year round or can die off in the winter with just the stalks surviving the cold temperatures (Global Invasive Species Database, 2021).


Biodiversity - Due to its ability to grow in various environments such as sun or shade in damp, disturbed or undisturbed areas, Lygodium japonicum is highly competitive and can dominate an area with a dense ‘wall’ of biomass, resulting in the exclusion of native species that can no longer grow due to lack of light (Bohn et al., 2018). 

Socio-economic - Lygodium japonicum can reduce access to various recreational activities such as hunting and hillwalking, resulting in a negative economic impact as people may not be able to use previously suitable sites for various recreational activities (Bohn et al., 2018).


Lygodium japonicum may be found in various habitats such as wetlands, grasslands, woodland, cultivated areas of gardens and parks, man-made drainage ditches and riverbanks (Bohn et al., 2018).


Lygodium japonicum reproduces in a manner typical of ferns, alternating between gametophyte and sporophyte generations (CABI, 2021). The gametophyte is the sexual phase of reproduction and sees the production of gametes (sex cells). The sporophyte generation is the asexual phase of reproduction and sees the production of spores. Spores produced by Lygodium japonicum are 64-80 mm (CABI, 2021). Lygodium japonicum is capable of self-fertilisation which may improve its ability to become naturalised in new areas (CABI, 2021). Sporophytes can reach sexual maturity within 5 weeks of germination therefore, Lygodium japonicum can reproduce relatively rapidly (CABI, 2021).

Mechanism of impact

Competition, Flammability

Management approach

As Lygodium japonicum is listed as an Invasive Alien Species of Union concern under the EU Regulations of Invasive Alien Species, it cannot be imported, traded, or released to the wild. Measures must also be taken to prevent spread of existing populations of it (European Commission, 2017).
If working in close proximity to a known population of Lygodium japonicum or travelling from a country where it is established, all clothes, vehicles and equipment should be cleaned before entering a new area as the spores can adhere to these surfaces (CABI, 2021).

Chemical control
Lygodium japonicum can be chemically controlled through the application of herbicides such as glyphosate. The recommended approach is to cut or pull vines away and then spray the foliage with the herbicide solution to minimise spray drift and subsequent damage of non-target species (CABI, 2021). Best results will be seen where the population is re-treated multiple times over a select time period to ensue eradication of the invasive species (CABI, 2021).

Broad environment


Species group


Native region

Temperate Asia, Tropical Asia, Australasia


World distribution(GBIF)

Apart from its native distribution mentioned above, Lygodium japonicum can be found in South Africa, North America and Australia where it is either listed as introduced or invasive (Bohn et al., 2018). It is not currently known to be present in the natural environment in Europe (Bohn et al., 2018).

Native distribution

Within its native regions of Asia and Oceania, Lygodium japonicum can be found in a variety of countries (mostly Asia) such as Bangladesh, Bhutan, Cambodia, China India, Indonesia, Japan, North and South Korea, Thailand and Vietnam, to name a few (Bohn et al., 2018). In Oceania, it is found in Papua New Guinea (Bohn et al., 2018).

Temporal change

Records submitted to Data Centre in 2023

The following map is interactive. If you would prefer to view it full screen then click here.

How can you help

Report any sightings of this species to the National Biodiversity Data Centre, including a photograph, if possible.
Dispose of unwanted specimens in a responsible manner that does not allow them in to the natural environment.
Avoid purchasing this species for ornamental purposes.



Bohn, K., Brundu, G., Chapman, D., Frohlich, D., Hutchinson, J., Miller, S.R., Van Valkenburg, J. and Tanner, R., 2018. Pest risk assessment for Lygodium japonicum (Thunb.) Sw. [online] Available at: <> [Accessed 8 Jul. 2021].

CABI, 2021. Lygodium japonicum (Japanese climbing fern). [online] Available at: <> [Accessed 8 Jul. 2021].

European Commission, 2017. Invasive Alien Species of Union concern. [online] Luxembourg. Available at: <> [Accessed 25 Jun. 2021].

Global Invasive Species Database, 2021. Lygodium japonicum. [online] Available at: <> [Accessed 8 Jul. 2021].

Invasive Species Ireland, 2021. Lygodium japonicum. [online] Available at: <> [Accessed 8 Jul. 2021].