This tree is epiphytic when young and forms a hollow trunk with light grey fibrous bark. It has upright branching from the base that forms a rounded crown of dark green oblong leaves. The mat-crimson saucer-shaped flowers appear in clusters during summer.

Hardiness zones 8 to 9 

Metrosideros robusta is naturally found in the north and south islands of New Zealand growing in bush-land. It attains a large size and is host to other epiphytic plants and lianas. 

It prefers an open sunny position and grows in a moist well drained, moderately fertile slightly acid soil and tolerates drought but is frost tender.

Rata is a large slow growing tree that is planted for its habit and flowers. It is used in parks and large gardens as a specimen and tolerates open coastal to bushland settings. It establishes in 3 to 5 years and attains a height of 4m (12) in 10 years. Under cultivation it is slow growing. ID 1913

Note:
The tree starts as an epiphyte in a senile host tree producing aerial roots that attach to the bark, eventually becoming large and killing off the host.

Metrosideros (may-trō-SID-er-os) robusta (row-BUS-tah)

Myrtaceae (mir-TAY-see-ee)
Myrtle, Eucalyptus, Clove and Guava Family