A lot of people I have asked me over the years how to grow blueberries successfully in subtropical climates. The key to success is choosing the correct variety. Look for blueberry cultivars that are classed as Rabbiteye or Southern high bush.
Some commonly found cultivars to look out for in these two groups are; Biloxi, Sharpblue, Gulf Coast, Climax, Powderblue & Misty. Blueberries are relatively self fertile but some varieties will have far better cropping if planted with compatible varieties.
Keep an eye out for the NEW!!! “Blueberry Burst”: This is a brand new blueberry variety that has just been released onto the market and it has been reported that it will grow successfully in the NT and North Qld, as well as Sth East Qld and all areas of NSW. It is an evergreen variety growing to typically around 1-1.5m. Note: some varieties may be semi-deciduous or even fully deciduous.
So you’ve got your blueberry now what?
Here’s the big tip!
Grow them in pots!
In subtropical and tropical areas blueberries grown in containers tend to fair better and be far more productive. When grown in containers you can be sure to give your blueberries the right pH, good drainage, adequate moisture and no competition from other plants. Mulch thickly around your plants whether in the ground or in pots to keep the roots cool, retain moisture and suppress weeds. With pot culture you can move them around each season to take the greatest advantage of cooler spots in summer and more exposed sunny locations in the cooler months. Blueberries will grow in up to 50% shade but you will experience better fruit production when in a sunny location.
When growing your blueberries in containers use a potting mix for Azaleas and Camellias as this is made to have a low pH. Blueberries like a soil pH between 4.0-5.5.
When planting out or potting up your blueberry DO NOT disturb the roots, this can set them back quite dramatically. And remember not to plant them too deeply. For maximum cropping have a few plants that are same cultivar or type.
In the Ground: To test your existing soil for pH you can easily buy a pH testing kit from a garden centre or hardware store. To make alkaline soils acidic can be a slow process but the addition of sulphur or peat moss and organic matter in the form of well-rotted manures and homemade compost should rectify this. You can even use the Azalea and Camellia potting/planting mixes in this application also. Make sure your soil is free draining and friable and be sure to mulch thickly with some tea tree or pine bark type mulch to keep the root zone cool and moist. I have to say I have had much better success in Brisbane growing my blueberries in pots rather the in the ground.
Fertilising: A slow release organic fertiliser applied during the growing season and every 2-3 weeks a liquid feed with fish emulsion or seaweed is ideal during the growing season. If in the ground the use of well-rotted cow manure also is acceptable.
Watering: In pots during warm weather water at least every 2 days, water until you see a small amount of water coming out of the bottom of the pot. In winter reduce your watering to every 4 days depending temperatures and wind. Blueberries require even soil moisture and the use of rainwater is preferable over tap water if possible.
Pests: Top of the list are possums and birds consuming the berries green and blue – netting is the best option and needs to be put on as soon as the fruit start to form.
Fungal issues: Blueberry rust or powdery mildew can be controlled with the use of an organic fungicide.
And lastly a little patience, it will take your blueberries bushes a couple of seasons to start fruiting to their full potential.