Kuta and Kāpūngāwhā

Kuta

In the literature, as well as in the natural habitat, there can be some confusion about which reed or sedge is ‘real’ kuta. There are two reeds that are very useful for weaving, and the same common names are often used for either plant.

The plant we name as kuta is the sedge most widely used in Northland. The hollow stems are used for making soft articles.

The soft, flattened, hollow stalks (culms) of kuta are a popular resource for weavers. The long culms are harvested, placed under matting for about 3 days to flatten, then woven into soft hats, mats, and kete. Kuta dries to an attractive golden-brown shade.

Description Eleocharis sphacelata

Kuta is a tall grass-like plant found in shallow, freshwater habitats. It forms clumps of densely packed, bright-green or yellow-green stems (culms) that arise from woody underground stems (rhizomes). The stems emerge as much as 1.5 m above the water surface, and total stem length may be as much as 3 m.

They are round in cross section, hollow and thin walled. The stem interior is divided into sections by regular cross walls (septa), about 1 cm apart, some of which are visible from the exterior, giving the stems a distinctive ringed or bamboo-like appearance.

Leaves are reduced to a single grey or brown papery sheath around the base of the stem, with an oblique opening through which the stem emerges.

Numerous small flowers are produced in a single, compact, erect spike at the tip of the stems. Spikes are covered with tightly packed, spirally arranged, overlapping fawn-green scales (glumes). Only the stigmas, at first white then shrivelled brown, emerge from the scales.

Distribution

Kuta is found throughout the North Island, but is less common south of Lake Taupo. It occurs in south Marlborough, Nelson, Westland, Fiordland, Southland, and Stewart Island, and is very rare in Canterbury.

It is found in swamps and on lake edges with the rhizome and usually the lower part of the stems submerged, in water up to 2 m deep, and occasionally in 3-m-deep water. Kuta grows from sea level to about 800 m above sea level. Although native to New Zealand, kuta is also found in Australia and Papua New Guinea.

Kuta maintains water clarity

Dense mats of rhizomes and roots in beds of kuta help stabilise bottom sediments and therefore assist in maintaining good water clarity. The tall hollow stems of kuta efficiently pump oxygen down to the rhizomes and sediment, enabling it to grow in deeper water than most other emergent aquatic plants. The stems also pump waste gases, including methane from bottom sediments, back to the atmosphere. By increasing aeration of these sediments kuta enhances debris decomposition and nutrient turnover.

Threats

Kuta is threatened by introduced Chinese grass carp which are now established in many North Island waterways. It is very palatable to grass carp and can be completely eliminated, along with other aquatic plants, from water bodies with heavy carp infestations.

Propagation

Propagation can be difficult. The New Zealand Plant Conservation Network website (www.nzpcn.org.nz) states 'fresh seed germinates best if allowed to float on water overlaying potting mix, gradually reduce the water level so that the germinating plants can naturally float on to the underlying soil'. Kuta will do best if their rhizomes are kept submerged.

Kāpūngāwhā

The second reed has been renamed, but was formerly included in a species found all over the world, Scirpus lacustris, whose spongy stems are used in many countries for making mats, containers, and the seating part of rush chairs.

Description Schoenoplectus tabernaemontani

Kāpūngāwhā is a tall, spiky, sedge found in shallow, freshwater and estuarine habitats. It can grow in more brackish habitats than kuta, and is found on the margins of rivers, lakes and ponds up to 300 m above sea level. Growth is seasonal with stems dying back over winter.

When it isn’t in flower, it is similar in appearance to kuta and some rushes (Juncaceae), with clumps or extensive patches of apparently leafless, bluish-green, round stems (culms) about 0.5–1.0 cm in diameter, emerging from standing water.

Stems arise from red perennial woody rhizomes up to 1 cm in diameter that bear masses of short, reddish, fibrous roots. The stems may be nearly 3 m tall.

They are round in cross section, with white spongy pith.

Leaves are reduced to several loose, grey-brown, papery sheaths around the lower 30 cm of the stem.

Flowers and seeds are produced in numerous reddish-brown spikelets, held to one side at the top of stems.

Uses

Harvested in summer, the stems of kāpūngāwhā are hung in bundles and dried. When completely dry, they can last for years before being used. The dry stems must first be dampened before being used for plaiting mats and baskets.

The plaited stems dry to a similar golden-brown/reddish shade as kuta (Eleocharis sphacelata). The stems are not hollow like kuta, so are not as soft, but are more hardwearing. The stems contain white spongy pith, which gives some insulation when used to make sleeping mats. Other recorded uses include whitebait scoop nets and kete.

Distribution, habitat and ecology

Kāpūngāwhā is found throughout the North Island. In the South Island it is found in southern Nelson, Marlborough and Westland, as well as at Christchurch and in and near Te Waihora Lake Ellesmere.

Kāpūngāwhā is tolerant of pollutants, growing vigorously in nutrient-enriched water, and taking up and storing large quantities of nutrients, particularly nitrogen and phosphorus. These characteristics, and its ease of propagation, have made this plant popular for use in artificially constructed wetlands for treatment of sewerage and agricultural wastewater in New Zealand and overseas. (The species used in several North Island artificial wetlands is S. californicus, planted before its immigrant status was realised.)

Propagation

Propagation from rhizome cuttings is straightforward. Cuttings, 30–40 mm long, are initially propagated in 100 mm of water under 75% shadecloth. After about 4 weeks, cuttings showing signs of growth are planted out. In artificial wetlands, cuttings are planted in gravel beds and grown hydroponically.

Distinguishing characteristics

Some distinguishing characteristics of kuta, kāpūngāwhā, S. californicus, and Baumea articulata (often found growing with kuta).