New Zealand has many excellent private gardens if you can organise access to them. The easiest way round this is to book a garden tour - the tour operator will do the leg work for you in gaining access to private gardens.
The English settlers brought English gardening traditions with them. Christchuch is known as the "Garden City". The Botanic Gardens are of particular note, both for its native and exotic collections. New Zealand has nearly 2000 endemic vascular plants. You will find a variety of garden styles - some gardeners focus native flora exclusively and some combine natives with exotics to great effect.
The diversity of landscapes and climates - alpine, coastal, subtropical, subantarctic and temperate - has allowed plants to evolve to match differing conditions. Western Nelson, at the northwestern tip of the South Island, is of particular botanical interest - local endemics include Clematis marmoraria. There are now restrictions preventing the introduction of exotic plants into New Zealand to protect the native flora.
If you can time your visit right, the annual Ellerslie Flower Show takes place in November in Auckland. It is the largest garden show in the southern hemisphere and showcases New Zealand's horticulture, garden design and garden art.
The New Zealand Gardens Trust was established by the Royal New Zealand Institute of Horticulture to develop a database of endorsed gardens. Professional assessors evaluate gardens for endorsement as a Garden of National or Regional Significance. The highest density of Gardens of Significance is in Taranaki.