Metrosideros umbellata Southern Rata or Ironwood
The best and easiest place to see the Southern Rata in full flower is on the western slopes of Arthur’s Pass in the South Island on the western slopes of the Southern Alps between the summit and historic Otira township. Arthur's Pass is also a great place to walk amongst the mountain flora.
Waitangi Day (6 February) is a great calendar date to remind people to head for this area to see the large round headed trees in full flower with their blood red flowers covering the tops of the trees.
Unfortunately it does not flower really well each year. Some suggest it is every 3 -4 years although some trees can be found in flower every year. When most trees are in full flower it is a spectacular site covering the steep mountain sides with a red glow.
This tree grows up to 18 metres tall with a trunk up to 1 metre in diameter although it can easily be multi trunked from the base. Once above the surrounding trees it forms a dense round headed tree and flowers appear all over the rounded canopy.
Its leaves are tough and leathery, dark green above and pale green below yet each leaf is an attractive lanceolate shape about 4 -7.5cm long and 1.2 - 2 cm wide. The underside is covered in oil glands and the midriff is easily seen. Around the edge of the leaf is a conspicuous continuous vein.
The blood red flowers feature short petals and sepals while the up to 2.5 cm long anthers are also blood red and numerous. The individual flowers are borne on cymes (a special flat topped grouping of flowers) with the stamen providing most of the colour as the sepals and petals are quite small.
Southern Rata is found from Kaitaia in the North Island to Stewart Island on the wetter western side of both islands and grows from near sea level to 1050 metres.
Its timber is very strong as it has to withstand very strong winds and other weather forces. It does not rot either.
If grown in the garden it takes many years to flower. Some experiments were undertaken to propagate it from cuttings of flowering shoots but unfortunately there are no results of this work. More research on this would be welcome.
In the wild it is a spectacular tree to see flowering. Well worth the wait for a good year and the trip to Arthur's Pass. While there take a day walk up the Bealey Spur .