Nuts and olives have been successfully grown in New Zealand since the earliest days of European settlement, but a concerted attempt to establish nut and olive industries only began in the 1980s.
Walnuts (Juglans regia) grow on large deciduous trees from Central Asia which reach a height of 25–35 metres and have a productive lifespan of over 50 years. In New Zealand they grow best in a dry climate on well-drained soils.
Most walnuts eaten in New Zealand are imported. After trials in the 1980s, two high-performing varieties, Rex and Meyric, were selected as the basis for a fledgling industry. In 2002, 479 hectares was planted in walnuts, mainly in Canterbury.
Macadamia trees (Macadamia integrifolia, M. tetraphylla) are tall, evergreen and native to the rainforests of eastern Australia. They were first grown in New Zealand around 1932, at Kerikeri. Both species grow well in coastal regions of the upper North Island, and a hybrid cultivar, Beaumont, is grown commercially. Most orchards are in Northland and Auckland. In winter the crop is picked by hand or harvested mechanically from the ground.
Four chestnut (Castanea) species are grown worldwide for their nuts. Chestnuts are medium-to-large deciduous trees, native to the northern hemisphere. Their nuts are produced inside a prickly seed case known as a burr.
In New Zealand most of the commercial plantings are grafted hybrid cultivars of the Japanese chestnut (C. crenata) and the English chestnut (C. sativa). They grow well on free-draining soils throughout New Zealand. Most chestnuts are grown around Auckland, but they are also a popular crop in Waikato and Canterbury.
The olive (Olea europaea) is a hardy evergreen tree originating in the Mediterranean. Olives have been grown in the upper North Island since at least 1835. Although there were various attempts to establish an olive industry, nothing developed until the late 1980s. There were three reasons for this:
- Until the 1980s, most New Zealanders were unfamiliar with Mediterranean and Middle Eastern cuisine and culture.
- The varieties grown here gave low yields and were not suitable for extracting oil.
- Imported olive oil and table olives were cheap.
Commercial olive-growing began in Blenheim after Gidon Blumenfeld imported new cultivars from Israel in the late 1980s. The Ponder Estate planted a grove of the new imports, especially the Barnea cultivar. In the 1990s, oil from the Blenheim olives received an extra-virgin rating – the highest standard. Once it was known that New Zealand could produce high-quality olive oil, interest in growing olives blossomed. By 2006, 1 million olive trees had been planted over 2,600 hectares, evenly split between the North and South islands.
Olives in the park
John Logan Campbell, a founding father of Auckland, tried to start an olive industry in the 1870s and 1880s, importing seedlings from South Australia. Although the trees grew well, their yield was low and the oil’s flavour disappointing. Later, Campbell gifted some of his land to the nation. In 2007 this area, now called Cornwall Park, still contained several large olive trees from the original plantings.
Olive trees are productive for over 100 years. They grow in a wide range of soils and thrive in soils with a pH of up to 8.5. The harvest in New Zealand is between April and June.
In 2004 the domestic olive oil market was worth $2.3 million and exports earned $600,000.