Mikoikoi
Botanical name: Libertia ixioides
Synonyms: Sisyrinchium ixioides, Libertia tricolor, Moraea ixioides, Ferraria ixioides, Nematostigma ixioides, Renealmia ixioides, Tekelia ixioides
Common name(s): Mikoikoi, native iris, New Zealand iris, tūkāuki, mānga-a-huripapa, tūrutu
About
Libertia ixioides is a widespread endemic New Zealand perennial belonging to the iris family, Iridaceae. It forms dense fans of stiff, sword-like leaves from short, extensively branched rhizomes and is particularly distinctive for foliage that can develop strong yellow, orange or bronze tones when exposed to full sun. In spring it produces white iris-like flowers with yellow anthers, usually held amongst rather than well above the foliage. These are followed by large barrel-shaped capsules that change from green through yellow to black before partially opening to reveal vivid tangerine-orange seeds. It is one of the most commonly cultivated New Zealand Libertia species.
Natural habitat
Occurs from coastal to montane environments in a broad range of open and semi-open habitats. It is locally common on rocky ridges, cliffs, coastal bluffs, gullies, river banks and within upland forest. Rocky environments are particularly characteristic in parts of the South Island.
It grows both in open sunlight and partial shade and has even been recorded growing epiphytically on other plants at some northern North Island sites.
Growing environment
Extremely adaptable and grows successfully in full sun to partial shade. It tolerates a broad range of soils provided they are reasonably well drained and is particularly suitable for rocky banks, slopes and other relatively exposed positions.
Strong sunlight commonly causes the foliage to develop yellow, gold, orange or bronze coloration. Plants in partial shade generally remain greener. Established plants tolerate frost, wind and periods of seasonal dryness, although regular moisture encourages stronger growth.
Endemic distribution
Endemic to New Zealand and naturally widespread across the North Island, South Island and Stewart Island/Rakiura.
In the North Island it occurs from the far north southward to Wellington, although it is naturally less common around East Cape. It is widespread through much of the South Island and extends to Stewart Island/Rakiura.
Older reports of the species from the Chatham Islands are no longer generally accepted as representing naturally occurring Libertia ixioides.
Height
Leaves approximately 150–1,160 mm long, although mature plants commonly have foliage around 550–900 mm high. Flowering stems are generally held within or around the height of the foliage rather than conspicuously above it.
Width
Mature clumps commonly reach approximately 30–80 cm across and gradually expand through their short, branched rhizomes and stolons. Old plants can develop into considerably broader colonies where left undisturbed.
Flowering
September–December. White flowers approximately 8–25 mm across are produced on narrow, branched inflorescences. Flowers are usually held amongst the foliage rather than above the leaf tips. Each branch carries approximately 1–6 flowers, often two.
Fruiting
Fruit may remain present throughout much of the year. Large barrel-shaped capsules approximately 7–25 mm long and 5–14 mm diameter develop after flowering. They mature from green through yellow to black before partially splitting open. Older capsules fade to a pale tan colour and contain distinctive bright tangerine-orange seeds.
Uses
Native garden borders
Mass planting
Rockeries and rocky banks
Forest-margin planting
Coastal gardens
River-bank and slope planting
Native revegetation
Erosion-control planting
Containers
Low-maintenance landscaping
Feature planting for colourful foliage
Wildlife and biodiversity gardens
Appearance
Growth habit: A robust evergreen perennial producing dense fans of upright, sword-like foliage. Leafy fans are closely grouped on short, extensively branched rhizomes and connected by short stolons, creating compact but gradually expanding clumps.
Leaves: Approximately 150–1,160 × 3–12 mm, stiff, narrow and sword-like, with both surfaces similar in appearance. The bases are pale red-green. Numerous longitudinal veins are present, with the central veins crowded together to form a pale midrib. Leaf margins are often finely rough or scabrid.
The foliage is especially notable for its response to sunlight. Leaves exposed to strong light frequently develop yellowish, golden, orange or bronze tones, while shaded plants remain considerably greener. This natural colour variation has contributed to the species’ popularity in cultivation.
Flowers: Approximately 8–25 mm diameter with six widely spreading white tepals. The three outer tepals are narrower, elliptical and flattened, approximately half the length of the inner tepals. The three inner tepals are broader and orbicular-elliptical with a slight cleft at their tips. Yellow anthers approximately 2 mm long form a contrasting centre. Flowers are generally carried within the upper foliage rather than prominently above it.
Fruit: Large, barrel-shaped capsules approximately 7–25 × 5–14 mm. Capsules progress from green through yellow to black as they ripen. Unlike Libertia grandiflora, they open only partially through short longitudinal splits, and the old valves do not spread widely apart. Mature capsules eventually fade to pale tan.
The seeds are approximately 1–2 × 1–1.5 mm, rounded or occasionally angular and striking bright tangerine-orange.
Ecology
A versatile component of coastal, lowland and montane vegetation, occupying rocky and disturbed habitats as well as open forest. Its tolerance of exposed conditions and relatively poor substrates allows it to persist on cliffs, ridges and banks where competition from taller vegetation may be reduced.
The flowers are pollinated by insects, while the small seeds are thought to be dispersed at least partly by wind after being exposed within the partially opened capsules.
The foliage also supports native invertebrates. Leaf-mining weevils of the genus Microcryptorhynchus are known to utilise Libertia ixioides, demonstrating its role as a host plant within native ecological communities.
The species is currently classified Not Threatened.
Associated habitats
Occurs in coastal and inland cliffs, rocky bluffs, ridgelines, gullies, river banks, forest margins and upland forest. It is particularly frequent in rocky environments and other sites where the vegetation remains relatively open.
Associated plants vary greatly across its extensive geographic range but can include species such as karamū, harakeke, mānuka, kānuka, koromiko, native grasses, sedges, ferns and a wide variety of forest and shrubland species.
How to grow
One of the easiest New Zealand Libertia species to cultivate. Plant in full sun to partial shade in reasonably free-draining soil. It tolerates a wide variety of soil types and generally requires little attention once established.
Full sun is preferable when strong foliage colour is desired. Plants grown in exposed sunny positions frequently develop attractive yellow, bronze and orange tones, particularly as the foliage ages. Partial shade produces softer, greener growth.
Water regularly during establishment. Mature plants are relatively tolerant of dry periods but perform best with occasional moisture during prolonged summer drought.
Old leaves can be removed to maintain a tidy appearance, and spent flower stems may be cut away after seed collection. Large clumps can be divided periodically and replanted.
For restoration planting, locally eco-sourced material is preferable because the species occurs across a very broad geographic range and regional populations may exhibit useful local adaptations.
Propagation
Very easily propagated from fresh seed or division.
Collect capsules as they mature and begin to darken. The bright tangerine-orange seeds can be removed and sown fresh into a moist, free-draining propagation medium. Fresh seed generally germinates readily.
Division is the quickest method of producing established plants. Lift part or all of a mature clump and separate it into sections, ensuring each division retains healthy rhizome, roots and at least one leafy fan. Replant promptly and maintain moisture while new roots establish.
The species’ naturally branched rhizomes make established plants particularly straightforward to divide.
Cultural use
Mikoikoi and tūkāuki are Māori names recorded for Libertia ixioides, with mānga-a-huripapa and tūrutu also recorded historically for the species. As with several native plants known by overlapping Māori names, care is needed when assigning traditional uses specifically to L. ixioides rather than to Libertia more generally.
Its widespread occurrence throughout much of Aotearoa means the plant would have been a familiar component of coastal, forest-margin and rocky vegetation across many rohe.
Garden value
An excellent native perennial combining architectural foliage, attractive white spring flowers and unusually colourful fruit and seed. Its foliage can be particularly striking in sunny positions, where the normally green leaves develop yellow, gold, bronze and orange tones that provide year-round interest.
The species is highly adaptable, hardy and forgiving, making it suitable for both specialist native collections and general landscaping. It works particularly well in mass plantings, rockeries, along paths, on banks and amongst low native shrubs where its stiff vertical foliage provides strong textural contrast.
Its relatively compact rhizomatous habit also makes it easier to manage than the strongly spreading Libertia peregrinans. For Nelson–Tasman gardens, its natural South Island occurrence, hardiness and tolerance of rocky and exposed conditions make it particularly well suited to both ornamental native planting and appropriately eco-sourced restoration projects.