Mikoikoi


Botanical name: Libertia peregrinans
Synonyms: None
Common name(s): Mikoikoi, native iris, New Zealand iris

About
Libertia peregrinans is a distinctive endemic New Zealand perennial of the iris family, Iridaceae. Unlike the compact clump-forming habit of many other native Libertia, it spreads by long, horizontal yellow stolons, producing leafy fans at intervals and eventually forming extensive colonies. Its stiff, sword-like leaves can develop spectacular copper, bronze and deep orange colouring in full sun, with prominent red or orange central veins. White iris-like flowers appear from late spring into summer, followed by orange, yellow or blackish capsules containing orange-brown seeds. Once considerably more widespread, L. peregrinans has declined substantially through habitat loss and modification and is currently classified Threatened – Nationally Vulnerable.

Natural habitat
Primarily a coastal and lowland species occupying sandy, peaty, gravelly or pumiceous substrates. Typical habitats include dune slacks and swales, coastal scrub, estuary and river-mouth margins, swamp margins and open, poorly drained ground beneath scrub.

On the Chatham Islands it also occurs within wet bog vegetation, including Sporadanthus-dominated communities.

Distinctive upland populations occur amongst leaf litter in predominantly beech forest, demonstrating a broader ecological range than its strongly coastal reputation suggests. Historical inland populations also occurred around the Central Volcanic Plateau.

Growing environment
Highly adaptable in cultivation and performs in full sun to partial shade. Moist but reasonably free-draining sandy, peaty or gravelly soils suit it particularly well, although it tolerates a wide range of garden soils.

Strong sunlight encourages the characteristic copper-orange foliage. Plants grown in more shade generally remain greener. Once established it can spread vigorously through its long stolons, so sufficient room should be provided.

It tolerates coastal exposure, wind and periods of wet ground better than many garden plants, reflecting its natural occurrence in dune slacks, swamp margins and other periodically damp habitats.

Endemic distribution
Endemic to New Zealand, occurring naturally in the North Island, South Island, Stewart Island/Rakiura and Chatham Islands.

Its distribution is now substantially more fragmented than historically. North Island populations have been recorded from western and southern areas, with former records extending north to Piha and inland onto the Central Volcanic Plateau. It occurs through parts of the South Island, particularly western and southern districts, and remains locally present on Stewart Island/Rakiura and the Chatham Islands.

Some North-West Nelson populations show hybridisation with Libertia ixioides, making careful identification and eco-sourcing particularly important in that region.

Height
Leaves approximately 130–700 mm long. Most plants form foliage around 30–60 cm high, with the relatively short flowering stems generally remaining within the height of the leaves.

Width
Potentially extensive. Long horizontal stolons produce new leafy fans at intervals, allowing established plants to spread well beyond 1 m and eventually form broad colonies where conditions are favourable.

Flowering
October–January. White flowers approximately 10–30 mm diameter are produced in narrow, usually closely branched panicles. The flowers and flowering stems generally remain amongst the foliage rather than rising conspicuously above it. Individual branches may carry approximately 1–7 flowers.

Fruiting
January–February, although mature capsules may persist considerably longer. Capsules are approximately 6–15 mm long and 4–10 mm diameter, ripening from green to orange, yellow or black. They can remain closed for up to a year after ripening, with the seeds eventually released as the capsule deteriorates.

Uses

  • Coastal restoration

  • Dune and dune-slack planting

  • Wetland and swamp-margin planting

  • Native groundcover

  • Mass planting

  • Coastal gardens

  • Banks and open slopes

  • Gravel and sandy gardens

  • Containers

  • Feature planting for bronze-orange foliage

  • Wildlife and biodiversity gardens

  • Ecological restoration within its natural range

Appearance
Growth habit: A rhizomatous, evergreen perennial producing fans of stiff leaves from far-spreading horizontal stolons. The stolons are approximately 3 mm in diameter and yellow, with leafy fans either crowded together or appearing at intervals. This strongly creeping habit allows the species to form substantial colonies and is reflected in the name peregrinans, meaning wandering.

Leaves: Approximately 130–700 × 3–9 mm, narrow, sword-like and similar on both surfaces. Numerous veins run longitudinally through the leaves, with the central veins crowded together and characteristically coloured red or orange. Leaf margins are usually smooth rather than noticeably rough.

Foliage exposed to full sun frequently develops striking copper, bronze, orange or reddish tones. The combination of copper foliage and raised red-orange central veins is one of the most useful field characters for distinguishing the species.

Flowers: Approximately 10–30 mm diameter, with six white tepals spreading widely. The outer tepals are usually more than half the length of the inner tepals, relatively narrow, oblong to oblong-elliptic and flattened. The broader inner tepals are obovate-elliptical and have a small cleft at their tips. The anthers are approximately 3–3.5 mm long and dark yellow-brown.

Fruit: Ovoid to barrel-shaped capsules approximately 6–15 × 4–10 mm. They mature through green to orange, yellow or black and are characteristically slow to open. Some remain intact for a year after ripening before gradually disintegrating and releasing their seeds. Seeds are approximately 1–1.5 mm diameter, nearly spherical and orange to orange-brown.

Ecology
Libertia peregrinans is an important component of specialised coastal, wetland-margin and lowland habitats. Its long stolons allow rapid vegetative occupation of suitable open ground and help plants persist where shifting sand, periodic disturbance or fluctuating moisture would disadvantage more rigidly clump-forming species.

Flowers are pollinated by insects. Seed provides a second means of colonisation, while extensive vegetative spread through stolons can create large colonies from individual established plants.

Despite being readily cultivated, the species has declined considerably in the wild. Coastal development, drainage and modification of wetlands, invasive weeds and browsing by cattle, sheep, horses and rabbits have all contributed to losses. Some historical populations were destroyed when habitat was used for rubbish disposal, while inland populations appear to have been lost through a combination of weed competition, habitat modification and collecting.

It is currently classified Threatened – Nationally Vulnerable.

Associated habitats
Associated with coastal dunes, dune slacks, swales, beaches, estuary margins, river mouths, swamp margins, peatlands, open scrub and poorly drained lowland ground. On the Chatham Islands it also occurs in bog communities.

Associated plants can include oioi, native sedges, rushes, flax, mānuka, wetland ferns and other species of open coastal and damp lowland vegetation. Upland forms may instead occur amongst leaf litter beneath beech forest.

How to grow
Very easy to cultivate. Plant in full sun where strong orange-bronze foliage is desired, or in partial shade for greener growth. It tolerates a wide variety of soils but performs particularly well in sandy, peaty or gravelly ground with reasonable moisture.

Water regularly during establishment. Once established, the extensive stolon system makes plants robust and allows them to recover readily from moderate disturbance.

Its spreading habit should be considered carefully when choosing a planting site. In small gardens it is best placed where its runners can be contained by paths, edging or containers. In larger naturalistic plantings, its ability to form extensive colonies can be highly desirable.

For ecological restoration, use locally sourced material wherever possible. This is especially important around Nelson and Tasman because some North-West Nelson populations show genetic and morphological influence from Libertia ixioides.

Propagation
Extremely easy to propagate by division. Sections of stolon bearing healthy leafy fans and roots can be separated from established colonies and replanted directly. The spreading habit means a single healthy plant can eventually provide numerous divisions.

Fresh seed can also be used and usually germinates readily. Collect mature capsules, extract the orange to orange-brown seeds and sow into a moist, free-draining propagation medium.

Seed propagation is preferable where maintaining genetic diversity is important, particularly for conservation collections and ecological restoration.

Cultural use
Mikoikoi is a Māori name associated with New Zealand’s native Libertia. Specific traditional uses attributable exclusively to Libertia peregrinans are not well documented, and records referring generally to mikoikoi should therefore be interpreted cautiously rather than automatically assigned to this species.

Its former widespread occurrence in coastal and lowland habitats means it would have formed part of the familiar native vegetation of many coastal areas before extensive habitat modification.

Garden value
One of the most visually distinctive New Zealand native irises. Its strongest ornamental feature is its foliage, which can develop rich copper, bronze, orange and reddish tones when grown in full sun. The raised orange-red veins provide additional colour, while crisp white flowers create a striking contrast during late spring and early summer.

Its long-running stolons make it particularly effective as a native groundcover, where it can gradually develop into broad drifts of colourful foliage. It is excellent for coastal gardens, naturalistic plantings, wetland margins and difficult sandy or gravelly sites.

For Nelson–Tasman planting, Libertia peregrinans is especially interesting because populations occur within the wider region and some North-West Nelson plants show hybridisation with L. ixioides. For restoration work, careful identification and local eco-sourcing are therefore particularly important.