Blueberries are one of the easiest berries to grow and a great plant for beginner and organic growers. They are relatively pest free and you can pretty much leave them to their own devices. It's my gift of choice for housewarming parties. Even if the owner is not a gardener, he or she always loves the idea of a blueberry plant.
There are three types of blueberries cultivated worldwide, Lowbush, Highbush and Rabbiteye, although in New Zealand we grow only the last two.
Highbush blueberries are the most common, although Rabbiteyes are becoming increasing popular.
Within the Highbush group there are Northern Highbush and Southern Highbush blueberries.
Northern Highbush varieties require a high winter chilling, at least 700 hours per year, while Southern Highbush varieties require about only 400 hours, making them ideal for the warmer north.
Northern Highbush varieties include ‘Duke', ‘Elliot', ‘Jersey' and ‘Nui', among others, while Southern Highbush varieties include ‘Blueberry Muffin', ‘O'Neal', ‘Southern Blue' and ‘Summer Blue'.
Highbush blueberries are deciduous and self-fertile, although another variety planted close by will produce a larger, better crop.
Rabbiteyes are evergreen and at least two varieties are needed for cross-pollination.
They are suitable for all parts of the country, although they don't like very cold conditions. Varieties include ‘Blue Dawn', ‘Blue Magic', ‘Centurian' and ‘Powder Blue', among others.
Rabiteye varieties crop much later in the season, from February to early April, whereas Highbush varieties will produce fruit from mid-November to mid-February. If you plant several different varieties from each group you can spread the fruiting season considerably.
Rabbiteyes are also more tolerant to drought (although regular watering is best) and less susceptible to the root rot phytophthora, although care is still needed with planting to avoid disease.
Blueberries like a free-draining, acid soil with lots of organic matter mixed in. Dig compost and a little peat into your soil or potting mix before planting.
Rabbiteyes are not as fussy as Highbush varieties and do not need such an acid soil. They will tolerate a pH of 5.5, whereas other blueberries grow best below 5.5, between 4.5 and 5.5.
Plants will grow more vigorously and produce better if planted in full sun, so choose a warm, sunny spot in the garden or patio.
Dig a hole three times the width of the pot and the same depth as the root ball. If planting more than one bush for cross-pollination purposes, plant no more than 3 metres apart.
Blueberries make an excellent low hedge. If planting a hedge, position about 75 to 90 centimetres apart.
Plants have a shallow root system, which means they don't have the ability to dig deep below the surface in search of water. Make sure you supply plenty of water during the growing season, particularly when flowers and fruit are forming.
The first year is critical for the establishing of young bushes, so don't skimp on the water.
If you have several bushes it may be worth investing in an irrigation system. Keep the immediate area around your bushes free of weeds and grass to cut down on competition for water and nutrients.
In the first three years, blueberries require only a light feed. You can apply a slow-release fertiliser in spring, but a continuous top-up of organic mulch will be beneficial. Compost is ideal, or an acidic mulch such as pine needles or peat.
Avoid mushroom compost and wood ash, both of which have a high pH level.
Some growers also recommend picking off any buds in the first year to allow for better growth.
Blueberries don't require a great deal of pruning other than the removal of diseased wood or weak growth. Fruit is borne on second-year wood, so if pruned regularly you won't get any fruit. After four or five years, the oldest branches may need cutting back to encourage fresh, vigorous growth. Any leggy growth can be cut out to encourage plants to bush up.
If you would like to increase your blueberry collection you can take softwood cuttings in early spring. Cut stems about 15cm long and strip the bottom leaves, leaving two or three at the top. Place the cuttings in a pot filled with sand and peat moss and leave in a warm, bright spot out of direct sunlight. Keep the pot moist and roots should form in about eight weeks. Grow on until plants are big enough to plant in the garden, or pot up into a larger container.
Blueberries are ready to pick when they have turned a nice deep blue. The fruit should easily pull away from the plant when ripe.
You can leave the fruit on the bush after they have turned blue to develop a more intense flavour, although left too long they will drop off.
You might want to throw over bird netting too, otherwise you could lose your fruit to the neighbourhood wildlife. And all those good antioxidant, anti-inflammatory, anti-microbial and anti-carcinogenic properties might be wasted on our feathered friends.
- The Southland Times