Story: Citrus, berries, exotic fruit and nuts
Page 4 – Blueberries, strawberries and blackcurrants
The Department of Agriculture introduced blueberries (Vaccinium species) in 1950 to provide a suitable crop on the acid peatlands of Waikato. This area remains the centre of blueberry production, with 341 hectares in cultivation in 2002. In 2006 blueberries were New Zealand’s most valuable export berry crop, worth NZ$12.5 million in fresh exports and $1.4 million as frozen fruit.
Blueberries require a well-drained acid soil with a pH of 4.0 to 5.5. Two kinds (highbush and rabbit-eye) are grown in New Zealand. Both have a productive life of 20–30 years.
Highbush blueberries (V. corymbosum and V. australe) originate in the north-eastern US, and produce early-season fruit. They are woody deciduous shrubs which may grow to 6 metres high. Harvest is from mid-November to mid-February (summer). Highbush blueberries are self-fertile, but need winter chilling to produce a good crop.
Rabbit-eye blueberries (V. ashei) grow naturally in the warmer regions of the south-eastern US. They produce late-season fruit, harvested from January (summer) to mid-April (autumn). These evergreen plants are not self-fertile, and need a pollinator plant nearby. They need less winter chilling than highbush species.
Strawberries (Fragaria x ananassa) are mostly grown for domestic consumption. About 6,500 tonnes are produced by 125 growers, and were worth $24 million in 2005. Fresh strawberry exports earned $3.9 million in 2006.
Originating from crosses of North and South American species, strawberries are small evergreen herbaceous plants. They fruit well for up to four years, but are grown commercially as an annual crop.
Strawberries grow well on a range of soils, from clay to sandy loam with a pH range of 5.5–6.5. They are planted on raised soil beds covered with black polythene. The plants are prone to infection by soil-borne diseases, and for many years growers fumigated the soil with methyl bromide – but in 2007, this substance was phased out.
New Zealand’s commercial strawberry fields cover a total of 170 hectares, mainly in the Auckland region. The fruit are harvested from spring to the end of summer, depending on the varieties.
Blackcurrants (Ribes nigrum) are cold-climate deciduous shrubs, which originated in central and northern Europe and northern Asia. Outside Europe, New Zealand is the largest producer of blackcurrants, accounting for 3% of the world supply.
When students Anna Devathasan and Jenny Suo measured the vitamin C content of their Ribena blackcurrant drink for a school project, they found only a trace – despite the advertising slogan ‘The blackcurrants in Ribena have four times the vitamin C of oranges’. The Commerce Commission confirmed the findings, and in 2007 manufacturer GlaxoSmithKline was prosecuted and fined more than $200,000.
In New Zealand most of the crop is grown in the Canterbury–North Otago area (1,000 hectares) and Nelson (400 hectares). The fruit ripens in December and January (summer) and is harvested by machine.
Blackcurrants prefer deep, fertile soils with a slightly acid pH, around 6.0–6.5. They have a productive lifespan of 15–20 years. The main variety grown is Ben Ard, a New Zealand-bred cultivar. Blackcurrants have more anthocyanin (a soluble pigment and antioxidant) than most other fruits, and have been promoted for their health benefits.
Domestic sales of fresh blackcurrants were worth $1.7 million in 2004. In 2006, export of frozen blackcurrant concentrate was valued at $9.8 million, and frozen fruit at $1 million. Much of the crop is exported to Malaysia as frozen concentrate, where it is made into the fruit drink Ribena.