This article was published in the Titirangi Tatler, March 2010
An Ecosystem in a Tree:
I was recently asked, "What is your favourite plant?" I chose the New Zealand puriri or Vitex lucens.
Call it heresy for a native plant nurseryman, but I'm choosing it because its structure is most like an English oak (Quercus robur) and I have lived all my life at the end of a long driveway lined with English oak trees that were planted more than 120 years ago. I love the ambience, their sheer size and presence. In addition the trees along my drive are supporting ecosystems of other plants, insects and birds. These are mostly native species and prove the validity of an argument put forward by the ecologist Dr. Geoff Park. He referred to "Middle New Zealand" where the native components of our environment meet the introduced exotic elements and make a mixed community.
One of my favourite patches of bush is on the North Shore where the original high spreading puriri survive with a massed gathering of different-aged nikau smothering the ground. Joining the two levels are vertical columns of supplejack stems which spiral directly upwards to gain a hold in the highest branches of the puriri. The thick clumps of "widow-makers" (Collospermum hastatum) adorn the puriri branches providing rich niche conditions for the shrubby epiphytes such as Pittosporum kirkii and P.cornifolium. A myriad ferns find a congenial home up there where the competition is less and the light is bright but still shaded. Hanging spleenwort, and its cousins Asplenium polyodon and A. obtusatum, Huperzia varia and Pyrossia eleagnifolia all cling tenaciously to their branches while across them all entwines the robust Microsorum pustulatum or hounds tongue fern. All of these species have also colonised my oak trees. In addition, the epiphytic tree, Puka (Griselinia lucida), and perching orchids, Earina and Winika, are also thriving there.
But puriri trees have other advantages. Apart from producing wood that makes great fence posts or coffee tables if you want something that will last forever, puriri trees have a long flowering period when they are covered in pink 'foxglove-like' flowers, and an even longer period of developing red fruit, making for all year interest for both humans and birds.
The woody seed capsule continues to fascinate me after 30+ years of growing it. The rugged, ribbed 'stone' has scales on 4 sides which allow moisture to penetrate the wood. This in turn swells the 4 seeds and they can all germinate together pushing the scales aside to emerge as 4 separate individuals clinging to their woody capsule. Survival of the fittest takes over and generally only one will eventually develop into the huge trees I know and love.
If you want a fast-growing tree that will bring a diverse ecosystem to your garden, puriri is the tree for you.