Gareth Carter: The pōhutukawa is one of my favourite trees

Pōhutukawa are not a quick growing tree by any means, with many established trees we see around the city likely 60-80 years old. Photo / Supplied

As a coastal town we have a few plants that thrive, that are distinctive to the conditions we have here. Other areas with the same climatic situation boast them too.

The pōhutukawa is the tree I’m talking about. This is one of my favourite trees, their spectacular red flowers offer a great show every year over the early summer months. They look so bright and vibrant against a blue sky on a summer’s day.

They are not a quick growing tree by any means, with many established trees we see around the city likely 60-80+ years old.

There are a number of varieties of the metrosideros species that are grouped together under the widely recognised common name of pōhutukawa that we see in parks and streets. Not all are giant forest trees and a number can be grown in the home garden with some smaller growing varieties suitable for patio pots.

Pōhutukawas have become very popular among many home gardeners. When New Zealand was settled by Europeans, they were found growing naturally close to the coastal areas of the North Island, from the Three Kings Islands southwards to Poverty Bay on the east coast and around the mouth of the Ureaui River, just north of Waitara on the west coast. They also grew along the shores of some of the lakes in the Rotorua district.

Since then many species have been extensively planted in many parts of New Zealand both inland and on the coast. They have been used as street trees in a number of cities including Whanganui and many have been planted in parks and gardens.

The largest pōhutukawa in New Zealand, Te Wahoa Rerekohu at Te Araroa, is said to be over 300 years old and has a height of nearly 21m and a spread of almost 40m.

We can also see good specimens in and around Nelson, on Banks Peninsular and as far south as Dunedin on the east and Jackson’s Bay on the West Coast of the South Island. It is well known that the pōhutukawa grows best by the sea. The familiar species Metrosideros excelsa is commonly referred to as the New Zealand Christmas tree.

The Māori name pōhutukawa, ‘drenched with spray’, refers to the way these robust trees cling to rocky cliffs and endure wild ocean storms. It can grow into a fairly massive spreading tree that overhangs the water, the huge branches growing out almost horizontally and form deep roots that enable the tree to cling to steep banks and rocks and remain there.

Pōhutukawa trees often have aerial roots growing from low branches or the trunk. They can form a tangled mat or net and may join around the trunk or branch from which they arise. Only the larger roots may reach the ground.

The key feature is the vivid summer display during December and January when the tree is often completely smothered with its orange-scarlet to deep crimson flowers. These comprise dense clustered stamens which open from powdery buds totally covering the tree. Fallen stamens can lay a red carpet on the ground.

Many birds are attracted to pōhutukawa flowers because of the copious nectar in the flowers. These trees are perfect in many landscaping situations. Coastal hardy, they are a good first choice as a front line seaside plant against prevailing strong salt laden winds.

In Whanganui they can be planted in most sandy to heavy clay to free-draining soil that has been deeply worked and enriched with organic compost in a full or partial sun position. Mulch 50mm to 75mm and water during dry periods while the trees are becoming established. Once established the trees are very drought resistant.

Pōhutukawa normally branch from the ground but a single trunk can be formed with careful pruning and staking.

As a hedge or screen, regular trimming encourages and maintains the desired size to form an almost impenetrable barrier.

Pōhutukawa also make good tub or container specimens for courtyard, patio or deck situations. They also do well for several years before requiring repotting or planting out. Most pōhutukawa varieties respond very well to being trimmed and can be kept significantly smaller than their growth potential by an annual prune.

Metrosideros excelsa is the species from which all the cultivars are derived. There is some considerable natural variation within the species throughout many plants in the wild. A number of selections have been made over the years, resulting in named varieties that are propagated vegetatively to offer surety of colour, size and growth habit. Some of these varieties include:

Māori Princess is what we would all recognise as the iconic traditional pōhutukawa with spectacular, deep crimson red flowers from December onwards into summer.

Metrosideros Springfire is an early flowering variety which has more orange-red coloured flowers from spring to early summer. It grows approximately 4m high by 3m wide.

Metrosiderous Lighthouse is a selection of Metrosideros excelsa from Rangitoto Island in Auckland. Lighthouse has a more upright and tighter form than other pōhutakawa. It has the same dark, rich, green, oval-shaped leaves, crimson red flowers and rough dark brown bark. Red aerial roots may develop on the lower portion of the trunk over time. With all the typical features of a normal pōhutakawa tree, Lighthouse is better suited to where a smaller growing is required. Hardy to coastal conditions. Can be kept clipped to 1.8m. Has a 4-5 metre height in 15 years and a mature height of 6-8m.

Metrosideros Maungapiko is a cross between southern rata and pōhutukawa that incorporates the frost tolerance of the former with the large profuse flowers of the latter. It grows approximately 2m high in five years and 5m high when mature.

Metrosideros Kermadecensis Variegata is a fine compact variegated form extremely hardy to coastal conditions and an ideal tub plant. The foliage is broadly margined creamy yellow and provides a garden with a distinct colour. Some good specimens are along the GF Moore Drive entranceway to Springvale Park in Wanganui. These began as 150mm high plants in the gardens in front of the Memorial Hall forecourt and were successfully transplanted to their current site in the 1970s by parks personnel of the day when they were too large for the gardens.

Metrosideros Tahiti is a good smaller form of pōhutukawa that will fit into a courtyard garden or pot. It forms a beautiful shrub that grows about 1.2m high by 1m wide. It produces brilliant red flowers 2-3 times a year mostly during the summer months. The foliage is a silvery grey with red tips on the buds making it most attractive.

Have a great week – slip, slop, slap, wear your sunhat and enjoy the weather and your garden.

For more gardening information visit www.springvalegardencentre.co.nz

Gareth Carter is general manager of Springvale Garden Centre