About

Metrosideros robusta, commonly known as the northern rātā, is a forest tree endemic to New Zealand. It grows up to 25 metres (82 ft) or taller, and usually begins its life as a hemiepiphyte high in the branches of a mature forest tree; over centuries the young tree sends descending and girdling roots down and around the trunk of its host, eventually forming a massive, frequently hollow pseudotrunk composed of fused roots. In disturbed ground, or where there are gaps in the forest cover, northern rātā will grow on the ground with a normal but short trunk.

How to grow it

Northern rātā may be propagated readily from fresh seed. Viability of the seed drops quickly after a few weeks or if it is allowed to dry out. Cuttings do not strike readily, but better results can be obtained from using water shoots.

At least three cultivars of northern rātā have been released. There are also known cultivars of hybrids between northern rātā and pōhutukawa (known as Metrosideros ×sub-tomentosa), and between northern rātā and southern rātā. Known cultivars include:

Where it grows

Northern rātā is found in the North Island from Te Paki in the north to Wellington in the south. Formerly widespread, it is now uncommon over large parts of its former range, and is apparently absent from all but the south-east of Hawke's Bay. In the South Island, northern rātā is common from Nelson to Greymouth and Hokitika. It reaches its southern limit near Lake Mahinapua at 42°4′ South latitude. The natural habitat is forest along the coasts and in the lowlands. In some parts of its range northern rātā occurs in montane forest. Formerly, with rimu (Dacrydium cupressinum) it was a dominant tree in a forest type known as rimu/rātā forest.

Other Metrosideros plants

White Flowering Rātā · Bartlett's Rata · Metrosideros boninensis · Crimson Rata · Metrosideros colensoi · Vunga · Small Ratavine · Metrosideros elegans · Pōhutukawa · Scarlet Rātā Vine · Metrosideros humboldtiana · Pohutukawa