General
Amerikanskt blåbär (highbush blueberry, Vaccinium corymbosum) and half-high hybrids (crosses with the lowbush V. angustifolium) are long-lived fruiting shrubs. Highbush types typically reach 1.5–2.0 m, while half-high cultivars stay 0.8–1.2 m and are hardier for colder sites. They require acidic soil (pH 4.0–5.5), even moisture, and mulching. Yields improve with at least two distinct cultivars that flower at the same time. Expect first meaningful crops from year 3–4 after planting, with peak yields around years 6–10. Protect from birds at ripening.
Light
Full sun to light partial shade; full sun gives highest yields and sweetest berries.
Soil type
Acidic, well-drained, humus-rich, peat-free ericaceous substrate with high organic matter. Sandy or sandy-loam with ample pine bark/wood fiber works well. Avoid calcareous soils.
Water requirement
Consistently moist but not waterlogged. Very sensitive to drought and salts; use rainwater if tap water is hard.
Nutrient requirement
Low to moderate. Use slow-release, chlorine-free, ammonium-based fertilizers for acid-loving plants. Avoid nitrate forms and heavy manuring.
Precultivation
Blueberries are usually propagated by cuttings or purchased as container plants. Seed raising is slow and not true-to-type. If experimenting with seed, stratify for 6–10 weeks at 2–4°C, then sow shallowly on acidic medium (pH ~4.5) under bright light; germination in 3–8 weeks at 20–22°C. For practical gardening, skip seed and buy 2–3 year old potted plants.
Planting
Plant in spring once days are reliably >8°C and soil is workable. Choose a sunny, wind-sheltered site. Prepare a wide planting pit or raised bed filled with peat-free ericaceous mix (e.g., composted pine bark + wood fiber + coarse sand). Space highbush 1.2–1.5 m apart (rows 2–3 m); half-high 0.8–1.0 m. Set root ball slightly shallow and mulch 5–10 cm with pine bark/needles or leaf mold. Water thoroughly with rainwater; keep pH low (avoid lime, ash, or concrete rubble). Containers: 30–45 L for half-high, 50–75 L for highbush, with large drainage and bark-based mix.
Pruning
Minimal pruning the first 2–3 years beyond removing weak or damaged wood. From year 3–4, in late winter (Feb–Mar), remove 1–3 of the oldest, thickest canes at the base to stimulate new shoots; thin crowded interior growth and low drooping twigs. After harvest (Jul–Aug), you can lightly tip-prune excessively long shoots and remove dead twig ends. Aim to maintain 6–8 strong canes of mixed ages per bush.
Maintenance
Mulch annually to preserve moisture and suppress weeds. Irrigate during dry spells, especially from flowering through berry sizing. Feed lightly in early spring and again early summer with acid-loving fertilizer or sulfur-coated ammonium sulfate; avoid overfeeding. If pH drifts up, use elemental sulfur in autumn and water with rainwater. Net plants before berries turn blue to protect from birds. In cold regions, choose half-high cultivars and site out of winter sun to reduce bark splitting.
Harvest
Pick in dry weather when berries are fully blue, including at the stem end, and detach with a gentle rolling motion—usually 3–7 days after first turning blue. Harvest every 3–5 days without stripping whole clusters; flavor improves if some hang a few extra days. Cool promptly to 0–4°C, keep berries shallow to avoid crushing, and wash only just before use. Ripe blueberries do not after-ripen; sort out pink or soft berries. Excellent for freezing unwashed, then rinse when thawed.
Common issues
Yellowing leaves with green veins (iron chlorosis) indicate too high pH or hard water—acidify and switch to rainwater. Drought leads to small, tart berries. Diseases include mummy berry and Botrytis in wet summers; improve airflow, mulch, and remove mummified fruit. Pests: aphids, sawfly larvae, and especially birds; use fine mesh netting. Winter dieback may occur on exposed sites—choose hardy half-highs and avoid late nitrogen.
Pollination
Partly self-fertile, but cross-pollination between two or more different cultivars greatly improves fruit set, berry size, and ripening spread.
Companion plants
Other acid-lovers: lingonberry (Vaccinium vitis-idaea), cranberries (Vaccinium macrocarpon), heather, rhododendron, azalea, dwarf conifers, and groundcovers like mosses and sedges.
Incompatible plants
Plants needing neutral/alkaline soils (e.g., lavender, thyme, many vegetables). Avoid adding lime, wood ash, or hard tap water.
