Juncus bulbosus
Environmental Weed (2024)
Common names
bulbous rush
Biostatus
Exotic
Category
Vascular
Structural class
Rushes & Allied Plants
Simplified description
Low-growing leafy rush to 25 cm tall (more than this in aquatic plants), leaves very fine, usually swollen at the leaf base, submerged leaves are fine and thread-like, up to 1 m long, plant often reddish with branched flowerheads made up of many small clusters of 2–6 yellow-brown flowers/capsules (fruit), but often clusters of leaves can be found on these flowers.
Flower colours
Brown, Green
Detailed description
Low-growing, variable perennial rush, 5–15 cm high, densely tufted or with prostrate rooting stems with leafy tufts at nodes, often mat-forming or submerged. Stems usually reddish-tinged, slender, swollen at base, rooting at nodes. Leaves tiny and bristle-like (narrow, grass-like on floating and submerged plants), with distinct hollow compartments separated by partitions. Inflorescence terminal, variable, unbranched and few flowered or branched and open, occ with tufts of bristly leaves. Flowers tiny, green to brown. Seed capsules 2–3 mm long, yellowish-brown.
Similar taxa
No other introduced rushes have the clumped filamentous leaves, swelling at the nodes, proliferous flower heads. In aquatic habitats the leaves are longer and more grass-like and may be confused with J. bufonius, but the stems swollen at the base and the septa (cross wall) visible in the leaves distinguish J. bulbosus from J. bufonius. The native Juncus novae-zelandiae is superficially similar but has black capsules and lacks the leafy proliferous heads.
Distribution
Widespread and common throughout.
Habitat
Mostly peaty sites in wet pastures, water body margins, drains and wetlands, sometimes submerged.
Conservation status
Not applicable
Detailed taxonomy
Family
Juncaceae
Synonyms
Verojuncus bulbosus (L.) Záveská Drábková & Proćków
Taxonomic notes
Subgenus Juncus, Section Ozophyllum (Septati) Kirschner (2002: Juncaceae 2)
Proćków et al. (2023) proposed a taxonomic segregation of Juncus into six genera based on molecular and morphological evidence. Whilst it has long been recognised that the current circumscription of Juncus includes morphologically divergent taxa—reflected in the recognition of numerous subgenera and sections—the consensus view of the NZPCN website taxonomy subcommittee, taking into consideration advice from Australian Juncus expert Dr Karen Wilson (NSW Herbarium) and others in Europe is that the generic segregations proposed need further consideration and testing. Accordingly, it has been decided to maintain the current broad circumscription of Juncus, but to include all new names as synonyms in factsheets. We thank, in particular, Dr Wilson for her helpful comments.
Ecology
Flowering
Spring to early summer
Fruiting
Summer to autumn
Year naturalised
1896
Origin
Eurasia and North Africa
Reason for introduction
Unknown, seed or soil contaminant.
Control techniques
Rarely controlled, but can be controlled manually, mechanically or herbicidally depending on situation.
Life cycle and dispersal
Seed dispersed by animals, water or contaminated machinery.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Other information
Etymology
juncus: From the Latin jungere ‘to tie or bind’, the stems of some species being used to make cord (Johnson and Smith)
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
JUNBUL
Referencing and citations
References and further reading
Champion, P. et al. 2020. Freshwater Invasive Species of New Zealand 2020. NIWA publication. https://docs.niwa.co.nz/library/public/FreInSpec.pdf
Healy, A. J. 1982. Identification of weeds and clovers. New Zealand Weed and Pest Control Society Publication. Editorial Services Limited, Featherston. 299 p.
Healy, A. J.; Edgar, E. 1980. Flora of New Zealand, Volume III. Adventive Cyperaceous, Petalous and Spathaceous Monocotyledons. Government Printer, Wellington. 220 p.
Johnson, P. N.; Brooke, P. A. 1989. Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319 p.
Johnson, A. T.; Smith, H. A. 1986. Plant Names Simplified: Their pronunciation, derivation and meaning. Landsman Bookshop Ltd, Buckenhill, UK.
Kirschner, J. (compiler) (2002). Juncaceae 2: Juncus subg. Juncus, Species Plantarum: Flora of the World Part 7: 1–336.
Proćków, J., Záveská Drábková, L. 2023. A revision of the Juncaceae with delimitation of six new genera: nomenclatural changes in Juncus. Phytotaxa 622(1): 17–41.
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Healy and Edgar (1980).
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.