Blueberries are one of the few fruiting shrubs many New Zealand gardeners get wrong for a reason that has nothing to do with sun, water or pruning. It's the soil. Blueberries need genuinely acidic soil, roughly pH 4.5 to 5.5, and most home garden soil in New Zealand sits much closer to neutral. A blueberry bush planted straight into an unamended vegetable bed will usually survive for a season or two, then stall, yellow and produce little fruit, while the gardener tries to fix a problem that was never about feeding or watering in the first place.
Blueberries need genuinely acidic soil, roughly pH 4.5 to 5.5, and most home garden soil in New Zealand sits much closer to neutral.
Test your soil pH before planting, not after the bush starts struggling. If it's above 5.5, work in elemental sulphur ahead of planting and expect it to take months to shift the pH, since soil acidity changes slowly. Digging in peat or backfilling a raised bed with an acidic mix helps more directly. If your soil is heavy clay or strongly alkaline, growing the bush in a large container filled with ericaceous (acid) potting mix is often the more reliable option than fighting the existing ground.
Blueberries go in as bare-root or potted plants over autumn and winter. In Northland, Auckland, Bay of Plenty, Gisborne and Hawke's Bay, plant from May through July. In Waikato, Taranaki, Manawatū-Whanganui, Wellington, Nelson and Tasman, the same May-to-July window applies. Further south, in Canterbury, Marlborough, the West Coast, Otago and Southland, wait until June or July. Give each bush full sun and space plants 1.5m apart; a mature bush reaches around 1.5m tall. This is a high-water shrub with shallow, fibrous roots, so keep a permanent mulch layer, such as bark or sawdust, over the root zone and don't let it dry out between waterings.
Remove any flowers that appear in the first year so the young plant puts its energy into roots rather than fruit. Flowering follows in spring, September and October in most of the country and October further south, when bumblebees do most of the pollinating work. Most varieties are self-fertile, but planting a second, different variety nearby noticeably improves fruit size and how much actually sets, so buy two varieties from the start rather than one. If leaves start yellowing between the veins while the rest of the plant looks otherwise healthy, that's chlorosis, and it usually means the soil pH has drifted back toward neutral and needs re-testing.
Birds are the biggest threat to a ripening crop and will strip a bush faster than any insect; net it as soon as the fruit starts to colour. Aphids are the other pest worth watching for. Botrytis, a grey mould, can take hold on ripening fruit in wet weather, so prune for airflow through the centre of the bush rather than letting it grow dense, and take out old, unproductive wood each winter. Root rot is the other real risk, and it comes from the opposite direction to underwatering: blueberries want moist soil, not waterlogged soil, so drainage matters as much as irrigation.
A blueberry bush takes two to three years to reach a proper harvest, and an established bush then produces around 2 to 5kg of fruit a season. Pick berries once they've turned fully blue; unlike some fruit, they don't continue ripening after picking, so an early-picked berry stays exactly as tart as it was on the bush. It's rated an intermediate crop for exactly the reason this guide starts with: get the soil chemistry right at planting and the rest of it is straightforward.