Key characteristics

• True rushes belong to the family Juncaceae. The two largest genera in New Zealand are Juncus, with 50 (including 17 native) species of wet and damp habitats and Luzula, 17 mostly native species, mostly confined to upland environments.
• The name ‘rushes’ is widely applied to plants with a characteristic growth form – usually rhizomatous, in loose or dense clumps, with more or less cylindrical, erect, more or less rigid, sharp-tipped, leafless or with leaves like stems and basal sheaths.
• However, some rush-like weeds (mainly of the family Cyperaceae) often grow with true rushes and can be confused with them. See Healy and Edgar’s or Champion et al’s book for further information. Two common coastal species are included in the descriptions below.
• Here we deal only with the tall leafless or apparently leafless rushes with upright cylindrical stems which are obvious and common weeds mostly found in damper pastures. Other rushes with leaves distinctly different to the stems are not dealt with here but some will be dealt with in Rushes – II.
• There are 20 species in this group (i.e. Rushes – I), with nine native species that include the four of the five more common species encountered.

Most important species

• Juncus australis forms loose open clumps in pastures and damp places throughout the North and South Islands but is less common in the south of the South Island. Its clumps often have thin centres, the stems are medium-thick, blue- to grey-green, dull and ridged. Pith (the white centre of the hollow stems) is often completely absent but if the stem is cut longitudinally with a knife, the knife makes a clicking sound as it passes the hard projections on the inner walls of the stems. It is rarely grazed and then only by cattle. Native to New Zealand.
• Juncus effusus (soft rush) is possibly the most abundant and widely distributed of all the species of leafless rushes, and occurs throughout the North and South Islands and Stewart Island, especially on peaty soils. It forms dense clumps of soft stems, readily compressed, easily broken and often grazed to the base. The pith is continuous and very spongy. The flower heads have many flowers and can be either lax or open, but the lowest branch is always curved downwards or is a dense round head. Introduced from the Northern Hemisphere.
• Juncus edgariae can be recognised by its very dense, tall (up to 2 m) clumps of bright green, shining, wiry, slender stems and the interrupted pith of dense consistency. It is very variable in form and is very abundant and widely distributed in damp pastures and swampy places in both the North and South Islands as well as on Stewart and the Chatham Islands. This species was until recently known as Juncus gregiflorus, an Australian species, but is now recognised as unique (endemic) to New Zealand.
• Juncus pallidus is a very tall and robust light or grey green rush up to 2 m tall. It has an uninterrupted pith and broad stems up to 8 mm across. It is native to New Zealand and is found throughout, especially in damp places near the coast.
• Juncus sarophorus grows in very tall, dense clumps up to 2 m tall. Its stems are wiry, blue-green in colour, dull and ridged, usually with interrupted pith. The flower heads are large and fan-shaped with many slender branches pressed against the stem. It is native to New Zealand, found in damp pastures and swampy places throughout the country.

Other leafless rushes and similar species found in coastal areas

• Juncus acutus (sharp rush) has a very scattered distribution in mostly sandy soils on the western coast of the North Island. It is a prickly upright rush forming dense clumps up to 1 m tall. Stems and leaves are light green in colour, ending in a very sharp point. Flower heads a dense cluster with distinctive large reddish-brown to brownish-orange capsules, 4.5-5 mm long.
• Juncus kraussii (sea rush) is found in coastal areas, especially the margins of salt marshes, but also in low-lying coastal pastures in the North, South and Chatham Island but absent in the southern part of the South Island. It forms open, yellow-green clumps up to 1.2 m tall, with open black or dark brown fan-shaped flower heads.
• Ficinia nodosa (knobby clubrush) is very rush-like but is actually a common coastal sedge found on a wide range of sandy soils. It forms dense upright clumps of shiny dark to yellow-green stems with a dense spherical dark brown flower head. It is found throughout New Zealand.
• Apodasmia similis (oioi) is a jointed rush (a family related to the true rushes), with characteristic dark joints (actually reduced leaves) regularly spaced wiry, dull grey-green or yellow dense stems often flowering at the tips. This species typically forms dense beds (up to 1.5 m tall) rather than individual clumps. It is a characteristic salt marsh plant also found in other wet coastal areas, found throughout and unique (endemic) to New Zealand.