Blueberries need a sheltered site in well-drained, moisture-retentive, acidic soil, (pH 4.5-5.5) in sun or part shade. If you can grow azaleas, rhododendrons and camellias in your garden, blueberries should be successful too.
Improve the soil before planting by removing all weeds and incorporating composted bark, bracken, leaf mould, pine needles or sawdust to a fork’s depth.
When planting, space highbush cultivars with 1m (3¼ft) all round and half-highs with 50cm (20in) all round. Mulch newly-planted blueberries with pine bark (composted or chipped) or leafmould. Make sure you have room for at least three blueberry plants, as they fruit much better with two cross-pollinating partners.
Watering and feeding
Keep the compost moist but not waterlogged and don’t allow the compost to dry out. If you can, water blueberries with rainwater, not with tap water, unless you have no alternative in a drought.
Feed container plants every month using a liquid fertilizer formulated for ericaceous (lime-hating) plants, following the manufacturer’s recommendations.
Mulch plants in open-ground, in spring and autumn with acidic or neutral organic matter, such as composted sawdust, composted or freshly chipped pine bark, pine needle leaf mould or standard leaf mould. Avoid manure and mushroom compost, as they tend to be quite alkaline in pH.
At Wisley, blueberries, unless growing on containers, need virtually no feeding; supplementing annual additions of organic matter with 15g per square metre (½oz per square yard) of sulphate of ammonia sprinkled round the plants in late winter. An alternative where plants are not growing well is to apply a fertilizer recommended for ericaceous (lime-hating) plants as directed by the manufacturer.
If you do not have an acidic soil, try growing blueberries in containers or raised beds filled with ericaceous compost; members report John Innes Ericaceous as being easiest to use.
Blueberries are not always fully hardy, and as with many plants, it is the combination of low temperatures and wet conditions that are most damaging. Put containerised plants indoors in a shed or garage during prolonged cold spells, or wrap the pot in hessian or straw to protect the roots. Protect flowers from late frosts with a double layer of horticultural fleece.
Pollination, fruiting & harvesting
Although many blueberries are self-pollinating, it is best to grow a minimum of three different cultivars to ensure reliable cropping.
Pick fruit when it is completely blue and has a white surface bloom. Fully productive plants around seven years old produce up to 6kg (14lb) of berries.
Pruning and training
Blueberries fruit on short sideshoots produced during spring or early summer of the previous year. They also produce a second late flush of fruit on the tips of the current year’s growth.
Pruning is rarely needed in the first two years, when it is best to simply aim for an open centred bush, removing any crossing or misplaced branches.
Prune any time over the dormant season (November to March), but ideally in late February or early March when the fruit buds can easily be distinguished from the leaf buds. Fat buds produce flowers and fruit, while smaller, flatter buds form shoots and leaves.
A mature bush should contain about one-third old, one-third middle-aged and one-third young stems.
- Dead, diseased, dying, weak, diseased, rubbing or damaged stems, plus any that are touching the ground
- Twiggy growth at the ends of the branches that fruited last year, cutting back to a low strong, upward-facing bud or branch
- One-third of the oldest stems at the base of a mature plant