Sunday, June 15, 2008

Rhopalostylis sapida

Nikau, Nikau Palm

Rhopalostylis is a genus of palms with tall smooth stems marked by the scars of fallen leaves. There are only two species known and they are confined to the South Pacific – one on Norfolk Island (with a variety on the Kermadec Islands) and the other to the mainland of New Zealand and the Chatham Islands.

The Nikau or Nikau Palm is an excellent plant for the garden and is characteristic of warmer parts of N.Z. The fronds spread out from a smooth attractive bulbose base and it has been known as feather duster palm. It has been described as a slow growing plant in home gardens and while that may be true it is very attractive in those young stages. In the right place it grows fairly quickly but will take a number of years to produce a stem.

This palm tree grows to about 10 metres high on a single great leaf scored stem. The leaves are up to 3 metres long; each divided up into long narrow sharp pointed leaflets. Maori used the Nikau leaves in the construction of their whares. A framework was made of manuka sticks and the roof and the walls composed of palm leaves which formed a watertight cover. The individual leaflets are shaped like a little channel that conducts the rain to the ground. Nikau whares are extremely pretty and picturesque but now rarely seen. The leaflets are also used for weaving into baskets and kits of every description.

In the right location, reasonably sheltered from wind and has some shade, it adds that tropical or subtropical touch the landscape. In nature groves of Nikau palms make a beautiful sight. It will tolerate a few degrees of frost so it will be difficult to grow in frosty areas of Christchurch and Canterbury. It is found growing naturally in native bush reserves on Banks Peninsula at Akaroa. It will grow nicely in frost-free areas of Christchurch.

They like rich moist and deep soil and like to grow in a group. It needs to be planted more in New Zealand gardens and some experimentation on climate range could see it used in places where it does not currently grow. When mixed with lancewoods, flaxes and other native plants it will help create a distinctive NZ look.

Propagation is by seed. The seed have been used by settlers for bird shooting when ammunition was scarce. Kakas find a foothold on the smooth stem and hang upside down to enjoy their meal. Collect the bright red fruit and sow one or two per pot. They do not like being transplanted and need to be sown direct into a pot. Care should be taken in potting them up into larger pots making sure they are not over potted. Once growing well plant out in the garden in its permanent position.

The unexpanded central bud and the very young spandix are both edible and were formally eaten by both Maori and European. Removing the Central Bud inevitably stops the plant growing and it will eventually die.

A characteristic of Nikau is its inflorescence or flower spike that is up to 35cm long. It grows under a leaf sheath and between two large boat shaped leaf stalks or spathe. When opening out they protrude from the trunk below the bulbous leaf structure. This much-spiked inflorescence expands and opens out when it is free of its leaf sheaths. Individual pinkish flowers are single sexed and packed onto the branches and followed by brilliant red hard fruits about 10 mm long containing a single large hard seed which takes about one year to ripen.

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