Metrosideros covers a wide group of nearly 50 species and hundreds of varieties. All are evergreen groundcovers, shrubs or towering trees. They are all native to the Pacific region especially the Islands of Hawaii, Micronesia, New Zealand and those around South East Asia. They are flowering evergreens of the Myrtle Family.
M macropus, M. rugosa, M. tremuloides and M. waialealae are all very similar species that are best distinguished by subtle differences in their foliage more than the soft, bristle-like red flowers that usually appear in summer. Some varieties can flower duing any of the warmer months of the year or whenever day length is somewhat longer than the hours of darkness.
.M. kermadecensis, the Kermadec Pohutukawa is from the Kermadec Islands north of New Zealand. It has rounded and smaller leaves plus rather variable blooms and growth habit. In the best microclimates this species can become almost rampant and creates a distinctive character to the native bush in these islands.
M. excelsa, the P˘hutukawa tree of New Zealand, is considerably variable in flower shape and colour as well as habit of growth. Some varieties can attain considerable height and width reaching 20-25m/66-82ft and even more! While other new seedling hybrids like the one pictures here are much more compact.
Flowers consist of a large cluster of stamens grouped together at their base and spreading outward in groups that can create a powder-puff of silky radiance. These flowers vary considerably in shape and size as well as colour from deep burgundy blooms through every shade of red; sometimes pink; while cream, green, orange, yellow and white forms have also been observed. These are almost always large trees well suited to open positions and coast sites in climates where severe freezing does not occur. They can survive on a variety of soils from basalt rock, to clay and even in boggy ground. Although they never naturalize on swampy land and often blow over as their root system does not expand properly in wet soils as it does over free draining land or rock.
They have been planted as ornamentals in Hawaii and many parts of subtropical Asia and The Mediterranean but do not appear to have naturalized there as they do in the Pacific .In parts of subtropical New Zealand and Hawaii, they have become indigenous. There they put on a brilliant display near the summer solstice. Thus they have been immortalized in New Zealand as their 'Christmas Tree'. Many Hawaiian traditions refer to the tree and the forests it forms as sacred to the fire Goddess, Pele..
and the Lake Goddess, Laka. Especially in Hawaii, they are often the first trees to spring up amongst grasses after lava flows begin to support new life. Therefore they have be given an almost mystical reverence as Ohia trees, representative of emerging or transformational new life.
M. polymorpha was originally classified as a variety of M colina native to Rarotonga and Tahiti. This is the dwarfest new Pohutukawa hybrid introduced fairly recently and is called Metrosideros Tahiti. Traditional Pohutukawas are often too large for the average section but M. Tahiti is a true dwarf growing no more than 2 m. in 5 years. The growth habit is very compact and bushy, creating an almost round shrub. In many situations M. Tahiti can be dwarfed or shaped with greatest ease to remain as dwarf as 1 m/3.3 ft or even less. In this situation it becomes a lovely flowering groundcover. This makes M. Tahiti an excellent subject for bonsai and container plantings. If left unpruned, over time, M. Tahiti can easily attain 2m/6.6ft or more, but in dry, hot and windy positions or boggy ground and without artificial watering little M. Tahiti often assumes the habit of a dwarf and spreading groundcover.
New growth is silvery white, almost woolly and more rounded than on traditional varieties. This silvery bloom holds on the new foliage for nearly a year before turning a lovely deep green. Foliage buds are scarlet red and are often mistaken for small flowers. But there is no mistake when Tahiti blooms. The radiant powder-puffs often smother the plant in blooms. But this display, as with most Metrosideros is a bit of a 'one-shot-wonder' being considerably spectacular one week and gone the next, especially if flowering coincides with rainy or stormy weather.
With M Tahiti and many of the other finer forms of Metrosideros, the large, round flower heads are vivid scarlet-orange and often 8-10cm across. Tahiti is very hardy and tolerates hot, dry coastal conditions, as well as cooler part shade. This variety is a superior container plant. While tender to freezing, it's durability means that in colder districts it can be wintered over in a sunroom or conservatory just like a holiday to the tropics.