Nikau (Rhopalostylis sapida) has a long peg root (i.e. it is deep rooted) - once planted outside it is best not to move it (though with care this can be done). In my experience nikau does best when planted in a rich, deep, well drained but moist soil. Seedling and juvenile stages should be sheltered from strong wind and heavy frosts. Some people suggest you should plant nikau in semi-shade but this is not essential. Some forms of nikau (which is very variable) do better than others, for example the Chatham Islands race is more tolerant of strong sunlight exposure, drought and the burning effects of wind and frost than some of the Northland forms. In their early stages nikau make excellent indoor pot plants. Hope that helps.