Birds don’t see the landscape in the same way as us. Although it is impossible to say with certainty that kereru are more indifferent to sweeping views than we are, their existences revolve more around signals like kowhai’s spring-flowering displays or the appearance of tawāpou’s vibrant fruits. Tawāpou is one of the less common inhabitants of our northern coastlines, due in large part to the damaging effect of rats (who consume the fruits and seeds, thereby preventing regeneration).
Aside from its ecological value as food for our largest forest birds, Planchonella costata should be seen more within plantings in northern New Zealand on the basis of aesthetics – as its upright growth habit and lush green foliage are highly desirable characteristics in a specimen tree. Tawāpou is our only native representative of a genus that extends through much of the Pacific and up to Southeast Asia.
In addition to New Zealand’s northern coastlines, P. costata occurs naturally on Norfolk Island, where it has the entertaining common name of ‘Bastard Ironwood’ – although the same title is also applied to another tree that we share with Norfolk Island, Nestegis apetala (bringing to mind the impression of a lot of disappointed people when they took to the forests of that part of the world).
Planchonella costata
When we look at our coastal forests, we are normally presented with an incomplete picture. The ‘missing pieces’ of these environments are not just interesting from an ecological point of view. They represent opportunities for landscapers and gardeners who are keen on exploring a wider range of characters for planting design. The tawāpou is one example of this; as it is a relatively small, elegant tree that has considerable potential as a landscape plant for northern New Zealand.
Whilst it is only found sporadically along the mainland, it is much more common on rodent-free islands, where seed predation is not an issue. The biggest trees that I have viewed are at Matapouri Bay (pictured below), where majestic specimens form part of the forest cover, as well as growing out in more open ground. Although it is capable of surviving in open conditions, its rate of growth during establishment is much slower than when it is able to push through existing vegetation.
The way in which the leaves are arranged along the branches is a particularly appealing attribute of tawāpou, as it gives them an orderly appearance and emphasises their upright growth habit. Although very old trees assume a more spreading form, they remain reasonably compact within plantings (and are amenable to pruning to maintain a suitable size for gardens). As with many trees, the lofty heights to which they grow within the wild (up to 15m) are not generally achieved in gardens (where they will reasonably attain between 4 and 7m).
The dark, shiny seeds of tawāpou have traditionally been put to an interesting use by Māori, who made necklaces from them. They are encased within the conspicuous fruits (pictured below), which can exhibit shades of orange, red and dark purple on the same tree.
Whilst it can tolerate a small degree of frost, P. costata is most suitable for cultivation in warmer parts of the country. It extends from North Cape to as far south as East Cape, although towards the south of its range, it is very sparsely distributed.