Throughout the rest of the year, however, I am also fascinated by the hanging brooms of aerial roots which remind me of overseas trips where I've seen subtropical Ficus species behaving in the same way, albeit to much more dramatic effect.
Support actIn coastal habitats around the North Island and the north of the South Island, the aerial roots of pohutukawa scramble across rock faces searching for crevices and pockets of soil to anchor into.
Here in the upper Botanic Garden, several specimens are growing as part of mixed tree and shrub borders.
One specimen in particular has developed a broad dome of foliage more than 20m high and nearly 15m across with the bottom 2m of its multiple stems completely shrouded in a skirt of aerial roots.
Many of these have reached down from the branches, rooted into the soil and thickened to form stout props accentuating the exotic subtropical impression.
Pohutukawa will grow in almost any well-drained soil, but grow particularly vigorously in well-fertilised soil.
•Located behind the upper garden public toilets, beside the driveway
•Pohutukawa can grow on near-vertical cliff faces
•A 1989 Forest Research report said 90% of coastal pohutukawa had been wiped out
•Project Crimson facilitates planting of 30,000 pohutukawa trees each year
•Can be clipped or pruned heavily
•Plant with roots in the shade
•Propagation is easiest from seed; cuttings can be difficult to grow and should be of semi-hardwood from mature plants.
- Doug Thomson is curator of the Rhododendron Dell at the Dunedin Botanic Garden.
