Raising the profile of a lance-like evergreen

In the latest instalment of our horticulture blog - all about the fascinating and diverse flora in our zoo grounds – we’re looking to New Zealand’s greater backyard to find a home-grown specimen found throughout Aotearoa.

Easily recognisable in their juvenile form, these indigenous evergreens are pseudopanax crassifolius, more commonly known as lancewood for their lancing spear-shaped leaves or horoeka in Te Reo Māori. A native tree with a prominent place in our grounds, these trees guard the entrance to our zoo, forming a cluster of long-limbed trunks underplanted with lush native greenery.

New Zealand has three distinct species of Horoeka plants with characteristically divergent juvenile and adult forms. The leaves are so dissimilar throughout the growth cycle of this endemic plant, that early botanists classified the same tree as two different species. This change in form over the lifespan of certain plants is called heteroblasty and is seen in several of New Zealand’s plant species.

During its juvenile years of growth, the trunk of the horoeka is tall and branchless with narrow strikingly linear leaves that rigidly extend down from the main trunk. Each leaf has sharply pointed teeth that angle toward the leaf tip. Once the horoeka is able to break through the forest canopy the stem tip begins to transform, branching out until it resembles a compact round-headed tree. The trunk with its characteristic rope-like twists and ridges, will start to thicken up until it reaches around 30 centimeters in diameter.

An interesting theory about the deviating forms of the horoeka is linked to the browsing habits of Moa in early Aotearoa. The leaves of the juvenile trees are tough, sharp and long – making them difficult for Moa to swallow and digest. Once the trees were able to burst past the height reached by these huge herbivores, it was safe for the leaves to grow larger and more leathery in texture. Earthy-brown in colour, seedlings are also able to blend in easily on the forest floor making them well camouflaged from large browsing birds. A second theory has to do with light conditions - once the horoeka breaks through the sheltered canopy, it is able to absorb the full sun and this may be what it requires to start its transformation.

This species is endemic to lowland forests and therefore found in much of the country, from Cape Reinga to Stewart Island / Rakiura. Not surprisingly due to its abundance, horoeka wood was used by Māori to fashion bird spears (maiere) to catch kererū, craft teka (darts), hïnaki (eel pots) and brushes (paraehe) making it part of New Zealand’s cultural history. The small yellow flowers that are produced once the tree has reached maturity are replaced by dark purple fruits that provide food for tūī and other endemic birds.

With their sculptural lines and compact habit, horoeka are a great tree to choose when the area for planting is at a minimum. These evergreen trees create a dramatic focal point to any garden without having to relinquish much in the way of space – and with the variations they bring, will delight for years to come.

Why not visit our zoo and relax in our stunning grounds! You can see our juvenile horoeka standing guard just before our zoo entrance and adult specimens can be found in the fernery adjacent to the central lake. We have so much appreciation for our amazing horticulture team and the work that goes in to keeping the zoos plant life lush and healthy. 

Stay tuned for the next blog in this series and if you have any recommendations on plants we should cover or questions for our horticulture experts, flick us an email!