Blueberries

Australian Blueberry Growers' Association

Blueberry growing regions and growing period of Australia. Australian Blueberry Growers’ Association

The Australian Blueberry Growers’ Association is the representative association of blueberry growers in Australia.

The Australian blueberry industry is expanding rapidly. Each year, Australian farmers produce around 4,500 tonnes of blueberries with a farm gate value of $A90 million. Of this 75 per cent is sold fresh within Australia, 15 per cent is exported to Asia and Europe and 10 per cent is processed, mainly as frozen product.

Blueberries are a native fruit of North America. The species comes under the genus Vaccinium which includes around 450 evergreen and deciduous shrubs. Three varieties of blueberry species have been identified; Highbush, Lowbush (wild) and Rabbiteye. Highbush varieties can be broken down into either Southern Highbush or Northern Highbush. Lowbush blueberries are not generally found in Australia.

Numerous cultivars have been bred from these varieties such as Misty (Southern Highbush), Denise (Northern Highbush) and Powder Blue (Rabbiteye) and they are commonly grown in Australia. These cultivars all have different characteristics, growing requirements and seasonal timing.

Blueberries were first introduced into Australia in the early 1970s. By 1978 it was recognised that the warmer climate Southern Highbush and Rabbiteye varieties (originally grown in the southern states of America) would grow on the NSW North Coast and produce high value, early season fruit. These varieties are harvested from June to February. Around 90 per cent of Australia’s blueberry production comes from northern New South Wales. In southern Australia, most of the blueberry production is based in Victoria (mainly in the Yarra Valley) and in Tasmania. The season starts in December and ends in April.


Kathy Keatley Garvey, UC Davis Department of Entomology

A well pollinated blueberry crop. Kathy Keatley Garvey, UC Davis Department of Entomology

Pollination information

There are two main types of blueberry (Vaccinium sp.) grown in Australia and New Zealand. These are Highbush, and Rabbiteye blueberries. Blueberry flowers are bell-shaped and hang facing the ground. There is a central stigma surrounded by 10 shorter anthers. The stigma often extends out of the flower. Blueberry flowers produce both pollen and nectar. Pollen is produced for up to 5 days.

A blueberry flower is capable of producing up to 50 seeds and berry weight increases with seed number. There are, however, factors other than seed number that also affect blueberry weights. Blueberries are insect pollinated. The most significant pollinators are honey bees that visit flowers to collect nectar and or pollen. In a study in Australia, honey bees comprised 95 per cent of all insect visitors. In New Zealand, bumble bees are also frequent visitors.

Stocking rates between one and 10 hives per hectare have been recommended; however, eight or more hives per hectare would seem appropriate for most blueberry crops. As a management tool it is good practice to mark and count flowers and then count the number of fruit produced to determine if pollination rates are optimized. Counting the seed number in fruit on a regular basis is also worthwhile.

Hannah Burrack, North Carolina State University

Honey bee pollinating blueberry flowers. Hannah Burrack, North Carolina State University

Highbush

The degree of self fertility of Highbush flowers appears to vary with variety and location. Most, however, appear capable of setting fruit without cross pollination and self-pollination frequently produces a similar fruit set. The number of seeds and fruit weight will usually be increased with cross pollination. It is also reported that that cross pollination may cause fruit to ripen up to a week earlier. If planting Highbush blueberries, it is important ask whether the cultivar would benefit from inter-planting with a second variety to ensure cross pollination. Even if a block of a single variety is already planted and producing, it may still be worth checking if better production could be achieved with inter-planting with another cultivar to ensure cross pollination.

Rabbiteye

Rabbiteye blueberry varieties are mostly self-infertile and cross pollination is required. When planting a second variety for cross pollination, the different varieties need to be in different rows if the fruit from each variety needs to be kept separate. The best design would be to have alternate rows of each variety. Not quite as good for pollination, but possibly easier to manage, would be to have every third row planted with a second variety.


Additional pollination information

Additional fact sheets and web links about the pollination of this crop are listed below. Please be aware that some of the information was developed overseas, and environmental and seasonal variations may occur.

Blueberry pollination fact sheet, The Pollination Program (Rural Industries Research and Development Corporation and Horticulture Australia Limited)

Blueberry pollination, CANOPLIN, Canadian Pollination Initiative, University of Guelph, Canada

Honey bees and blueberry pollination, University of Maine

Invest in pollination for success with highbush blueberries, Michigan State University

Bee pollination benefits for blueberries, Department of Agriculture and Food Western Australia

Reproductive growth and development of blueberry, University of Florida

Blueberry pollinators, North Carolina State University


References

The pollination information is an excerpt from Mark Goodwin (2012) Pollination of Crops in Australia and New Zealand. RIRDC Publication No. 12/059

The industry overview and graphs on the value of production and crop distribution are from the National Plant Biosecurity Status Report (2015), Plant Health Australia, Canberra