The cabbage tree (tī kōuka) - the wearer of many hats - is a fantastic tree that deserves more credit than it gets in its endemic home of New Zealand. It is a standout tree with its impressive, architectural trunk and leaf-head stretching to the sky, and has been used as an important resource for hundreds of years.
Cordyline Australis, commonly known as cabbage tree or tī kōuka, is found naturally in wetlands, forest margins, and riverbanks from the top to the bottom of the country. Sometimes growing up to 20 metres in height, and two metres in diameter, the largest known single trunk cabbage tree stands 17 metres tall and 9 metres in diameter in Golden Bay, estimated to be 400 or 500 years old.
Cabbage trees have a rich Maori history for use as food, fibre, and medicine. The stems, rhizomes, tips and leaf hearts, were all used as vegetables or to sweeten food. Cabbage trees were often grown and harvested instead of Kumara in the south of the South Island, as Kumara didn’t grow south of Banks Peninsula. Evidence of large cooking pits where cabbage trees were steam-cooked can still be seen in the hills of South Canterbury and North Otago, most of which are circular and have huge oven stones weighing upwards of 16kgs. The growing tip of the plant was used as a medicine and eaten raw, a drink made for stomach upset, and an ointment made from leaves used to rub on cuts, cracks, and sores. Fibre made from cabbage tree leaves is stronger than that from flax, and was valued for its strength and durability particularly in water, and eaves were used to make anchor ropes, fishing lines, cooking mats, baskets, sandals, and leggings. In parts of the South Island, cabbage trees were also used as route markers to direct Maori on their journeys, as boundaries, and to bury their kin. In places like Fiordland, Stewart Island, and the Catlins, cabbage trees are not naturally present, but were deliberately planted.
Flower spikes in spring attract natives birds such as kereru, bellbirds, parakeets, and tuis, who spread seeds in return for food and habitat. Lizards, caterpillars, and wetas are also commonly found with cabbage trees, and there are nine species of insect that are found only on cabbage trees, the best known of these being Epiphryne verriculata, the cabbage tree moth, which hides beneath the dead leaves, laying eggs at the base of the central unopened flower spike, and eat large holes and characteristic notches on the leaves.
There has been a decline in cabbage trees over the last 30 years due to a range of factors such as bacterial disease and rural decline in grazed land. They have become a staple in revegetation projects as they are a great colonising species as they need space to establish, have a dense root system which helps filter underground water flow, and provide bank stabilisation, and are extremely tolerant of wet soil making them great for planting in wetlands, and on riverbanks. The importance of using cabbage trees in projects such as revegetation or riparian planting is becoming increasingly pertinent as the decline of cabbage trees continues. Cabbage trees which self seed in areas such as in farmland or areas of stock use have a minimal chance of survival as stock grazes on the tender shoots of new seedlings and emerging sprouts. Fencing off these areas, or transplanting them to an area where they will be protected gives these seedlings the best chance of survival. Cabbage trees have an extraordinary ability to survive fire and clearing of land, and therefore were some of the last survivors of European settlement and clearing in many areas. It can renew its trunk from buds and protected rhizomes under the ground, regenerating quickly with the loss of competing plants. It is extremely versatile and resilient, thriving in both flood and drought conditions, and in marginal soil conditions.
In a residential garden, cabbage trees often have a bad rap. Leaves falling on the ground (and getting tangled in the mower) are one of the common reasons people don’t want to know about them. However, if you give them a chance you might find some surprising benefits. Cabbage trees make a great, hardy shelter - they are fast-growing and will bounce back from almost anything. The leaf heads will catch the wind and filter the wind, as well as attracting birds and bees to your garden in spring with their flower spikes. They also look great planted in a native hedge, with the grand trunk and leaf head protruding from the hedge once mature, attracting some amazing birdlife to your garden. The leaves are also full of turpentine oil and burn easily. A little work collecting fallen leaves and tying them into bundles will make your life easier come winter when it's time to light the fire, and you already have a collection of firelighters stocked.
So next time you are considering what to plant in your garden, give a thought to the good old cabbage tree - you might be well surprised - and make sure you include it in your rural and revegetation planting projects to appreciate it in all its glory.
Cordyline australis, commonly known as Ti Kouka/Cabbage Tree is a tall tree that, once mature, is a standout for its trunk structure. Cordyline australis can be grown in coastal, swampy, drought, or sun and wind-exposed locations. In summer, it … Read More »