Words & Photos: Dylan Norfield
The whiteywoods, or mahoe, are one of our most common native species, especially in disturbed sites or cleared land – they seem to appear as if by magic. The magic we talk about is the very efficient natural process of seeds being spread by birds. If you get a patch of whiteywoods that keep appearing each time you weed them out, then it is likely to be our feathered friends who are to blame. Perhaps the tree above is a favourite perch for kereru? Anyone lucky enough to have these hefty birds in their garden will often hear the raining down of seed beneath their perch.
Quite surprisingly, the whiteywoods belong to the violet family and make up a very diverse-looking genus. Surviving from some of the harshest inland central New Zealand climates, they also thrive down to temperate coastal locations. Many of the species have adapted to their relevant environment, being diverse in leaf shape, form and size. This adaptability makes them a great garden plant, you just need to pick the right species for the right climatic conditions in your garden.
The precise number of species found in New Zealand is still under debate and could range from 12 to 20 species and sub-species. Several have become readily available with a much larger number available from specialist native nurseries around the country.
The most readily available alpine species is Melicytus alpinus, which looks nothing like its more coastal counterparts. It is a plant that could easily be missed if out walking in the central South Island or southern North Island of New Zealand. Looking like a naturally pruned, small, leafless pile of branches, on closer inspection you can see the small leaflets and modified branches almost looking spiney. This has given it the common name of ‘porcupine bush’, with its intermingling branches enabling the plant to cope with heavy snow and drought-like conditions in summer. In the garden it is well-suited to rockeries and drier areas with full sun, but it is slow, so patience is needed.
For a good evergreen shrub for screening look no further than M. obovatus. It forms a great dense, green shrub relatively quickly, making it ideal as a hedging plant. It is the perfect alternative to many exotic plants, such as the usual buxus hedges that can be susceptible to disease, unlike M. obovatus, which is also not prone to pests. As a hedge it is easy to shear into shape, can be more informally pruned with secateurs or, if needed, more severely cut back with a saw or loppers where it will resprout again from old wood. It is not readily grown as a garden plant, but there is no good reason not to grow it. It is naturally occurring in several locations across the country, being tolerant of a range of conditions, except wet feet. If planting in a wetter situation, raise the planting area and add extra drainage to the soil.
M. ramiflorus is a very widespread species in New Zealand forests especially on disturbed sites. This is the species most regularly referred to as whiteywood, probably due to the wood’s very white appearance when cut. It forms a small tree to 10m tall, growing very rapidly as a young plant. Because of its ability to colonise new areas it is a great choice for revegetation projects, growing quicker than competing weeds. The berries are often violet-purple when ripe and are a favourite food for kereru and tuis, who inadvertently spread the seed around to help with the revegetation of new areas.
Growing the species is easy from seed. As the seed is insect pollinated, it produces large amounts of viable seed and the berries can be collected in late autumn before the birds get to them. If the berries are collected in a plastic bag they can be crushed with a little bit of water to remove all the flesh from the seed. Wash off as much flesh as possible using a fine sieve to collect the seed and sow immediately in a good seedling mix. Just cover the seed and the seedlings should germinate within six months of sowing. Once large enough, transplant to small pots and, when well rooted, plant out to their final location.