thumb|Botanical illustration of a pōhutukawa sprig by [[Ellen Cheeseman]]

Pōhutukawa (Metrosideros excelsa), or iron tree, is a coastal evergreen tree in the myrtle family, Myrtaceae, that produces a brilliant display of red (or occasionally orange, yellow or white) flowers, each consisting of a mass of stamens. The pōhutukawa is one of twelve Metrosideros species endemic to New Zealand. Renowned for its vibrant colour and its ability to survive even perched on rocky, precarious cliffs, it has found an important place in New Zealand culture for its strength and beauty, and is regarded as a chiefly tree (') by Māori.

Etymology

The generic name Metrosideros derives from the Ancient Greek ' or 'heartwood' and ' or 'iron'. The species name excelsa is from Latin ', 'highest, sublime'. ' is a Māori word. Its closest equivalent in other Polynesian languages is the Cook Island Māori word ', referring to a coastal shrub with white berries, Sophora tomentosa. The -hutu- part of the word comes from ', the Polynesian name for the fish-poison tree (Barringtonia asiatica; compare with and ), which has flowers similar to those of the pōhutukawa.

Description

thumb|right|The yellow-flowering "Aurea" cultivar

Pōhutukawa grow up to high, with a spreading, dome-like form. They usually grow as a multi-trunked spreading tree. Their trunks and branches are sometimes festooned with matted, fibrous aerial roots. The oblong, leathery leaves are covered in dense white hairs underneath. There is variation between individual trees in the timing of flowering, and in the shade and brightness of the flowers. In isolated populations genetic drift has resulted in local variation: many of the trees growing around the Rotorua lakes produce pink-shaded flowers, and the yellow-flowered cultivar 'Aurea' descends from a pair discovered in 1940 on Mōtītī Island in the Bay of Plenty.

Distribution

thumb|right|Metrosideros excelsa on [[Ponta Delgada, Azores, Portugal]]

The pōhutukawa's natural range is the coastal regions of the North Island of New Zealand, north of a line stretching from New Plymouth (39° S) to Gisborne (38° S), where it once formed a continuous coastal fringe. By the 1990s, pastoral farming and introduced pests had reduced pōhutukawa forests by over 90%.

Conservation

thumb|upright|A pōhutukawa in bloom

In New Zealand, pōhutukawa are under threat from browsing by the introduced common brushtail possum which strips the tree of its leaves. Inner bark extracts are used in rongoā (traditional healing) for the treatment of diarrhoea and dysentery, and the nectar used to treat sore throats.

The tree is used to create pōhutukawa honey, which is produced in areas such as Rangitoto Island. In parts of South Africa, pōhutukawa grow so well that they are regarded as an invasive species. The Spanish city of A Coruña has adopted the pōhutukawa as a floral emblem.

At least 39 cultivars of pōhutukawa have been released. Duncan & Davies nurseries were a leading force in the mid-20th century, while the late Graeme Platt has been responsible for 16 different cultivars so far, including a rare white-flowering tree. Cultivars include:

| Duncan & Davies

| Reddish stems and reddish-gold new leaves becoming butter-yellow and finally green with age. Sourced from M. excelsa 'Sunglow'.

|-

| M. excelsa 'Centennial'

| Lyndale Nurseries

| Compact, low-growing selection. Often incorrectly sold as M. tomentosa 'Dalese', especially in Australia.

|-

| M. excelsa 'Fire Mountain'

| 2003

| Melon Pink

| Robert Harrison

| Reverse-variegated cultivar from Australia. Grows to around . Grew from M. excelsa 'Pink Lady' under cultivation. 10–20% chance of variegation reverting.

|-

| M. excelsa 'Gold Nugget'

| Graeme Platt

| Early flowering (November). Sourced from Rangitoto Island.

|-

| M. excelsa 'Manukau'

A pōhutukawa tree with an estimated age of 180 years known as 'Te Hā' is fully established at an Auckland City park. 'Te Hā' is the largest urban specimen in the country. Plans to build a monument in honour of victims of the Erebus Disaster in proximity to the tree activated significant local opposition in 2021.

See also

References

Further reading

  • Rare Metrosideros E. Alley, at Sao Miguel Island, Azores, where it grows faster and larger than in its native habitat