Here south of Hokitika, 100 kilometres south of where most nikaus thrive, we have road-tested many young nikaus to destruction. The Great Freeze of 1996 took out the whole lot at minus eight. Under trees they can sit in a shivery minus six overnight and survive without damage. However a week of heavy rain followed by a hard August Freeze off the Southern Alps will knock them back at only minus three. This is because their fronds are swollen with rain and the juicy sap freezes inside the frond, turning it black and soft. You are lucky to even be able to save the middle frond, using layered frost cloth on a tree up to waist high. Snow will do the same thing. So a very wet frost, or snow, they don't like. Yet, under protecting trees, out of sight of any snowy mountain; given ample water on icy cold dry days, and using soluble seaweed supplements, we have overwintered hundreds successfully in our normal minus three or four degree winters.
4 year old youngsters under trees
Another of the nikau's secrets is revealed by its love of the Coast. As you struggle up river into the interior of the Paparoa Ranges up fabulous limestone gorges, the nikau-clad Pacific Island slopes suddenly change. Out of the sound of the mighty surf you turn a corner and the forest loses all the nikaus to hardier beeches and pongas. Local lore has it that the nikau loves the salt spray. Overwintering success using seaweed convinces me that this is true, and that the minerals and salts supplied by seaweed help nikaus and other trees like citrus, through frosty winters outside their normal range.
Wild nikau palms, Paparoas National Park
The number one killer of your first nikau palm is UV: sunburn from too much sunlight. In the wild the young palms grow under the deep shade of the adult fronds in a tight grove. They may only burst out into the full sun at head height or higher. So despite the idea of "palms loving warmth", these palms love shade, or at most partial sun. You can grow them in a tub and gradually give them more sun to harden them up over a few years. But planting one in the middle of your lawn in Blenheim or Hawkes Bay is asking for disappointment, unless it has its own shadehouse, sprinkler, and 2 metre tall ponga grove to protect it. Here in our seven metre rainfall we grow a mahoe tree in three years to 2 metres tall, and sit the young palms under it as a natural shadehouse.
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