This article was published in the Titirangi Tatler, September 2009
Good as Gold
Spring is that time of year when plants recognise the increasing daylight hours and warming temperatures. Most respond with a flush of foliage growth and then the development of flower buds. One native plant does things a little differently. Our three local forms of kowhai are deciduous species and drop their leaves through winter. At the approach of spring they put all their effort into producing flowers and forget about foliage development until the reproductive function is out of the way.
Kowhai is a member of the Sophora family, and our local forms are Sophora fulvida, Sophora microphylla and Sophora chathamica. Sophora fulvida is confined to Auckland's West Coast and a few scattered rocky bluffs, whereas Sophora microphylla and Sophora chathamica are both scattered across the Waitakere Ranges particularly along stream sides. As you drive through Titirangi or wander along bush tracks in the Waitakeres and see a glorious blaze of gold, it is because the naked trees provide an uninterrupted view of the mass flowering of this distinctive native tree.
Of course kowhai feature in many gardens as well, but they are often Sophora tetraptera which grow naturally in the Central North Island and along the East Coast. These are reputed to have slightly larger flowers but any minimal difference scarcely justifies compromising the purity of our local forms through hybridisation.
Kowhai often hybridise but pure forms have quite distinct foliage.
There are other forms from further south which are distinctive in their growth habit. Sophora prostrata is common in Marlborough and Kaikoura. It is generally a twisted, divaricating shrub with minute leaves and small orange flowers. Sophora longicarinata is an elegant species from NW Nelson where it prefers to grow on limestone bluffs.
Perhaps the most distinctive species is from Stephens Island in the middle of Cook Strait. Sophora molloyi is a large shrub as wide as it is tall and unlike all the other kowhai, it retains its leaves all year round. It is also notable for the long flowering period from June to September although it is not a massed display as in the other species.
All the species are attractive to both tui and woodpigeon. Tui love the nectar in the flowers and pigeon eat the foliage.
With its graceful foliage and deciduous habit, the kowhai gives a less dense effect in gardens than many other native trees.
Plant a kowhai today and enjoy its beauty for years to come.