Native Plant of the Month - February - Māhoe
Māhoe is a common tree that is found growing throughout New Zealand lowland and coastal bush. You are very likely to have seen these trees around Kaipātiki, even if you haven’t recognised them. This is an endemic species with several other closely related (and very similar looking) species growing in the tropics; on Norfolk Island, Fiji and Samoa. The Melicytus genus that māhoe belongs to is in the violet family, plants of which often have leaves with fine serrations along their edges, which you can clearly see on māhoe leaves. Within te ao Māori, māhoe is known as one of the trees that was bestowed with the secret of fire when the goddess Mahuika threw her last fiery toenail at Māui after he tricked her. Māori used māhoe wood in their fire-making practices as it has good qualities for kindling embers. Māhoe’s scientific name, Melicytus ramiflorus, roughly translates to ‘branch-flowering honey-cave’, which is a rather delightful description of the trees’ flowering characteristics.
Left: flowers on a female tree, right: flowers on a male tree
Māhoe flowers sprout out along the stems of their branches, which is a plant characteristic often seen in tropical plants and is called ramiflory. Like lots of our native plants māhoe are dioecious. This means that plants are either male or female and produce only one type of flower (male trees have flowers that produce pollen and female trees have flowers that receive pollen and develop into fruit). Māhoe flowers are small and pale green or cream coloured, but are usually very prolific and cover the branches of trees during spring, like fine lace gloves. Māhoe flowers have a cup (or cave)-like interior shape which pools with nectar and they are highly scented, especially at night. This abundant nectar and open shape means that they provide food for a wide range of insects, birds and geckos while they are in flower. Māhoe are very generous with their flowers, they generally begin flowering in late spring and individual trees can continue flower throughout the summer. Many trees will even have two flowering periods per year, one in spring and another in late summer. Māhoe fruit are small purple-blue berries and a tree in full fruit can look quite striking with branches covered in vibrant blue. In Aotearoa blue fruit are thought to have evolved to attract geckos for seed dispersal, so these may have had an important relationship with māhoe prior to the arrival of pest animals. Our birds are not put off by this hypothesis though and they also love to eat māhoe berries and spread their seeds far and wide.
Left: white lichen on māhoe trunk, right: hole suitable for a tree wētā in māhoe branch
A common name for māhoe is whiteywood. This refers to the large splotches of white lichen that develop on the trunk and branches as the trees mature. This is a very thin lichen that looks like white paint and appears to have a close and harmless relationship with māhoe trees. Often trees will have so much of this lichen that their bark looks like it is more white than brown. Old māhoe trees can grow knobbly trunks with lots of holes and hollows and wide bases. This gnarled shape provides lots of places for small birds and insects to shelter. Auckland tree wētā especially like to hide in these holes during the day before coming out at night to feed. Well established māhoe seem to have powerful abilities to regenerate and trees can live a long time, which is why they end up looking so twisty and interesting. Dormant buds just under the bark surface can suddenly sprout up if a tree is damaged or in response to the main trunk dying off. These new shoots will develop into young branches on the outer edge of the base of the trunk, even as the main trunk may hollow away. This is a form of self-coppicing and can cause an old māhoe to gradually form a circular thicket of branches around a hollow center where the original tree first germinated.
Left: bright green young leaves, right: leaf skeleton from old māhoe leaf
Young māhoe leaves are very soft and bright lettuce-green and are edible while they are still young and tender. They become too tough and bitter for people to eat once they mature, but kereru will still happily have a chew, as will possums. Like most of our native trees māhoe are evergreen, but some individual māhoe trees are semi-deciduous; they will shed a large number of their leaves in winter, and will regrow them in a vibrant green flush in spring. When old leaves fall and decay on the forest floor their vein network is often left, resulting in a carpet of pale leaf skeletons, which are especially noticeable under these semi-deciduous trees. In addition to this natural leaf-fall, māhoe sometimes lose a few leaves to the caterpillar of the māhoe stripper moth. This beautiful moth is endemic to New Zealand and while their caterpillars do some damage to māhoe, they rarely cause lasting harm, especially if there are plenty of birds about scouring trees for tasty insect treats.
Māhoe are commonly used in restoration projects because they are resilient trees that can cope with a range of conditions including full sunlight. They develop into a wonderful ‘nurse’ canopy for more light-sensitive forest canopy species and provide food and shelter for many native birds and insects. Māhoe look very similar to the invasive pest plant queen of the night and are a good replacement for this weed if you are thinking of removing it on your property. Queen of the night can be distinguished from māhoe by its small trumpet-shaped flowers and fleshy white berries. If you are interested in a bit of a plant identification challenge you can also look out for māhoe’s cousins around the place. Both Melicytus novae-zelandiae (commonly known as coastal māhoe) and Melicytus macrophyllus (commonly known as the large-leaved māhoe) can be found growing in reserves around Kaipātiki. Both species have dark green leaves that are much thicker in texture than māhoe; coastal māhoe leaves are smaller, more rounded and almost leathery to touch, while large-leaved māhoe leaves are shiny, smooth and often have very few teeth on their edges which are only near the leaf tip.