Overview
What blueberries need, how big they grow, and whether your soil will do.
Blueberries ask for one thing above all: acid soil, around pH 4.5 to 5.5. Get that right, in the ground or in a pot of ericaceous compost, and a bush can crop for more than 50 years, with white spring flowers and fiery autumn leaves thrown in. Plant two or three varieties together: they cross-pollinate for bigger berries, and birds will want them as much as you do.
Quick facts
- Botanical name
- Vaccinium spp.
- Soil pH
- 4.5 – 5.5
- Feeding
- Light feeder
- Height
- Up to 200 cm (79 in)
- Propagation
- Cutting
Growing details
- Frost sensitivity
- Frost hardy
Growing calendar
- Plant out: March, April, October, November
- Harvest: July, August, September
- Prune: January, February, March
While dormant: autumn in mild areas, early spring in cold ones. Berries go on sweetening for several days after they turn blue. Late winter, while dormant, from the third year.
Is this plant right for you?
- Needs acid soil
- Container friendly
- Frost hardy
- Perennial fruit
- Autumn colour
- Best with two varieties
- Crops for decades
Good to know
It stands frost, so it can go out earlier than tender crops.
Before You Grow
Test the soil first. Then choose a type hardy for your winters, and two or three varieties to pollinate each other.
If rhododendrons, azaleas and camellias thrive near you, blueberries probably will too.
What you need
A soil test
Blueberries need pH 4.5 to 5.5. Test before you plant. See acid soil.
Two or three varieties
Two- or three-year-old plants. Cross-pollination gives bigger crops. See choose your blueberries.
Ericaceous compost or acid organic matter
For pots, raised beds or improving the planting hole.
An acid mulch
Pine needles, bark, sawdust or leafmould. Never manure or mushroom compost.
A water butt
Rainwater keeps the soil acid. See watering.
Netting or a fruit cage
Birds take the berries. See pests.
Choose your blueberries
Choose a type hardy for your winters first: northern highbush suits USDA zones 4 to 8, and half-high types colder areas (OSU). Then pick varieties that ripen at different times, of the same type so they can pollinate each other (OSU).
Types. Northern highbush, the usual garden blueberry, grows 1.8 to 2 m (6 to 7 ft) and is very hardy. Half-high types are northern crossed with lowbush, 60 cm to 1.2 m (2 to 4 ft), and very cold hardy. Southern highbush and rabbiteye types suit mild-winter regions: OSU warns that southern highbush blooms so early in cool temperate areas that frost takes the flowers.
Size. From about 50 cm (20 in) to 2 m (6½ ft). Compact varieties such as ‘Bluetta’ or ‘Sunshine Blue’ suit pots and small gardens.
Pollination. Most blueberries are partly self-fertile, so one plant will fruit, but two or three varieties that flower together give larger berries and bigger crops. Half-high types and some varieties, such as ‘Brigitta’, need a partner.
Season. Varieties ripen from midsummer into early autumn, so an early, mid and late variety stretches the harvest.
Buying. Two- or three-year-old plants, pot-grown or bare-root; Illinois advises against paying extra for older ones.
Varieties compared
-
Earliblue
- Size (H x S)
- 1.8 x 1.8 m (6 x 6 ft)
- Season
- Early
- Notes
- Large, light blue berries; good autumn colour
-
Duke
- Size (H x S)
- 1.5 x 1.5 m (5 x 5 ft)
- Season
- Early
- Notes
- Flowers late, fruits early: good for short seasons. RHS AGM
-
Spartan
- Size (H x S)
- 2 x 1.5 m (6½ x 5 ft)
- Season
- Early to mid
- Notes
- Large, sweet berries. RHS AGM
-
Bluecrop
- Size (H x S)
- 1.2 m x 90 cm (4 x 3 ft)
- Season
- August
- Notes
- Self-fertile but better with a partner; dislikes wet soil
-
Brigitta
- Size (H x S)
- 1.8 x 1.8 m (6 x 6 ft)
- Season
- Late August
- Notes
- Large fruit; needs another variety to pollinate
-
Pink Sapphire
- Size (H x S)
- 1.5 x 1.5 m (5 x 5 ft)
- Season
- Summer
- Notes
- Deep pink fruit and pink flowers
-
Northblue
- Size (H x S)
- 75 cm (2½ ft)
- Season
- Mid
- Notes
- Half-high; very hardy; large fruit
Sizes from Gardeners’ World and UNH. For pots, a compact or half-high variety; for crops, two or three varieties that flower at the same time.
Where blueberries grow best
A sunny, sheltered spot with moist but free-draining acid soil. Blueberries grow slowly: about ten years to reach full size (UMN), and plantings crop for more than 50 years (OSU).
Frost. Plants are hardy, but open flowers are frost-tender. Good air movement reduces spring frost damage to blossoms; avoid low, still frost pockets.
Away from trees. Trees shade the bushes, compete for water and food, and cut air movement, which encourages disease.
In pots. Blueberries in containers are more exposed to cold, as the whole root ball sits above ground. Gardeners’ World gives about -12 °C (10 °F) as the limit for short periods; insulate pots in hard winters.
Spacing. 1 to 2 m (3¼ to 6½ ft) apart depending on the variety’s size (RHS); compact types 75 cm (2½ ft).
Sun. Full sun gives the best crop and the best autumn colour. UNH calls full sun all day essential for maximum production.
Partial shade. Blueberries tolerate it and still give a reasonable crop (RHS), but too much shade means fewer flowers and less fruit (UMN).
- Soil pH
- 4.5 to 5.5
- Time to full size
- About 10 years
- Planting life
- 50 years or more
- First good crops
- 2 or 3 years after planting
Acid soil: the one thing that matters
Blueberries must have acid soil, high in organic matter, moist but free-draining. In ordinary neutral or alkaline soil they turn yellow, stop growing and fail.
Test first. The sources give slightly different targets: 4.5 to 5.5 (RHS), 4.5 to 5.0 (UNH), 4.8 to 5.2 (Illinois), 4.0 to 5.0 (UMN). Above about 5.5 is too high.
Lowering pH. Mix in elemental sulfur, a season or a year before planting, as it takes months to work. Follow the product label: clay needs about twice as much as sand. Sphagnum peat or acid organic matter such as pine bark or sawdust acidifies faster, but peat has environmental costs.
Amend the whole bed, a strip 60 to 90 cm (2 to 3 ft) wide, not just the planting hole: the roots spread out.
Not suitable? On alkaline, only slightly acid or heavy clay soil, grow blueberries in a raised bed or a large pot of ericaceous compost instead.
Keep it acid. Soil pH creeps back up over the years. Retest every year or two and add sulfur as needed.
Planting
Plant while dormant into acid, well-drained soil, or a large pot of ericaceous compost.
Pick off the flowers for the first two years so the bush builds roots and shoots.
When to plant blueberries
Plant while the bushes are dormant, between mid-autumn and early spring.
Mild areas. Gardeners’ World prefers October, when the soil is warm and moist. Pot-grown plants can go in at any time except in hot, dry weather or frozen or waterlogged ground.
Cold areas. UNH and UMN plant in early spring. Bare-root plants usually arrive dormant then; keep them cool, dark and moist until you plant, and soak the roots for a couple of hours first.
Prepare ahead. If the soil needs acidifying with sulfur, do it the autumn or year before.
How to plant blueberries in the ground
Into soil tested and, if needed, acidified in advance.
-
Clear the weeds
Blueberries are shallow-rooted and don’t compete well.
-
Dig a wide hole
About twice the width of the roots. On poor soil, mix acid organic matter such as pine needles, leafmould or composted conifer bark into the soil you took out.
-
Loosen pot-bound roots
Rough up the outside of a tight root ball with a gloved hand.
-
Plant at the right depth
At the depth it grew in its pot, with soil just covering the roots. Don’t plant it deeper. No fertiliser in the hole.
-
Firm, water and mulch
Water thoroughly, then mulch with acid material such as pine bark or needles, clear of the stems.
-
Cut back and remove flowers
Sources differ on pruning at planting: OSU removes 30 to 40% of the bush, Illinois half to two-thirds, and UMN only broken or dead branches. Remove all flowers this year and next.
Planting blueberries in pots
The answer if your soil isn’t acid: a pot lets you start with the right compost.
-
Choose a big pot
At least 30 cm (12 in) across for a young plant and 45 to 50 cm (18 to 20 in) for a larger one (RHS). OSU uses about 38 L (10 gal) for half-high types and 57 to 76 L (15 to 20 gal), or half a barrel, for northern highbush.
-
Fill with ericaceous compost
Peat-free and soil-based. Gardeners’ World mixes in an equal volume of sharp sand or grit. The pot must have drainage holes.
-
Plant at the same depth
Firm in well and water with rainwater.
-
Pot on in spring
Move into a slightly larger pot if it needs it.
-
Top-dress each spring
In other years, replace the top layer of compost with fresh ericaceous compost.
Care
Rainwater, acid mulch, a light acid feed and yearly pruning keep a bush cropping.
Water with rainwater: hard tap water slowly makes the soil too alkaline.
Care through the years
Years one and two
Flowers: pick off · Prune: only damaged wood
Build the bush: remove flowers and any fruit buds, and water well. See pruning.
Spring
Mulch: pine needles or bark · Feed: ericaceous, lightly
Mulch and give a light acid feed if needed. See feeding.
Summer
Water: rainwater, evenly · Net: when the first fruit turns blue
Water while berries swell and net them against birds. See watering.
Autumn
Test: soil pH
Enjoy the leaf colour. Check the soil pH every year or two.
Late winter
Prune: a quarter of the old wood
From the third year, prune while dormant. See pruning.
Watering blueberries
Blueberries have shallow, fibrous roots and suffer quickly in drought. They need steady moisture, never waterlogging.
Use rainwater. Tap water is usually alkaline, especially in hard-water areas, and used regularly it raises the soil pH (RHS, Gardeners’ World). Keep a water butt for them.
How much. About 2.5 cm (1 in) a week in the growing season (Illinois). Water newly planted bushes well through their first year or two. Established plants in good soil need water in dry spells, especially while the fruit swells, which UNH calls a critical time.
In pots, water regularly to keep the compost just moist.
Mulch 5 to 10 cm (2 to 4 in) deep with acid organic material, topped up as it rots. Illinois found mulched plants gave significantly bigger crops, even when watered.
Feeding blueberries
Blueberries need only light feeding, and dislike too much fertiliser.
In the ground, the RHS finds bushes in regularly mulched soil need nothing more. If crops are poor or leaves show deficiency, give an ericaceous granular feed in early spring.
Acid feeds. Use fertilisers for acid-loving plants, such as those for rhododendrons and azaleas, or ammonium sulphate, which supplies nitrogen and helps keep the soil acid (Illinois). Illinois waits four weeks after planting before the first feed.
In pots, feed with a liquid fertiliser for ericaceous plants: every two to three weeks from April to August (RHS), or weekly in the growing season (Gardeners’ World).
Signs. Light-green or red leaves in summer, or little new growth, usually mean the pH has drifted up, or the plant needs nitrogen (UMN).
Pruning blueberries
Blueberries fruit on one-year-old wood: the fat buds at the tips of last year’s shoots are flower buds. Pruning keeps a steady supply of young, productive stems.
Years one to three. Prune very little: remove only dead, damaged, crossing or rubbing branches, and pick off flowers for the first two years so the bush grows.
From the third year, prune each year in late winter while dormant.
- Remove dead, diseased, broken and crossing branches, and low branches lying close to the ground.
- Cut out about a quarter of the oldest stems at ground level: thick, pale grey wood that no longer makes strong new shoots.
- Keep the younger stems, two or three years old, reddish-brown and covered in fat fruit buds. UNH keeps six or seven vigorous stems per bush.
Why it matters. An unpruned bush produces small berries: OSU finds even a large-fruited variety crops small berries if poorly pruned, and feeding won’t fix it.
Flowers and pollination
Blueberries flower in spring with small white or pink bells, pollinated mainly by bumblebees and other native bees. The more bees visit, the more fruit you get.
Cross-pollination. Most varieties set some fruit alone, but pollen from another variety flowering at the same time gives larger berries and bigger crops. Half-high types and varieties such as ‘Brigitta’ barely fruit without a partner.
Frost. Open flowers are damaged by late frosts. If frost is forecast at flowering, cover plants with fleece overnight or move pots under cover (RHS).
Blueberries in containers
A pot of ericaceous compost is the way to grow blueberries where the soil is neutral, alkaline or heavy. For planting and pot sizes, see planting blueberries in pots.
Water regularly with rainwater: pots dry out and are the first to suffer in drought.
Feed with an ericaceous liquid feed through the growing season. See feeding.
Check the pH every year.
Winter. Insulate pots with fleece, hessian, bubble wrap or straw in hard frosts.
Watch for vine weevil, which can be a problem in containers (Gardeners’ World). See pests.
Problems
Most blueberry trouble traces back to soil that isn’t acid enough, or to birds.
Common blueberry problems
These are growing problems, not pests or diseases.
Yellowing leaves, green veins
- pH too high
- Chlorosis
Iron chlorosis: the soil or compost isn’t acid enough, so the plant can’t take up iron. Left alone it can kill the bush. Test the pH, water with rainwater, add sulfur or repot into fresh ericaceous compost, and feed with an ericaceous fertiliser. Chelated iron gives a quick, temporary fix.
Pale or reddish leaves in summer, little growth
- pH
- Nitrogen
The pH has drifted up, or the plant needs nitrogen. See feeding.
Small berries
- Pruning
- Variety
Mostly the variety, then pruning: an unpruned bush crops small fruit. See pruning.
Few or no berries
- Young plant
- Frost
- No partner
Young bushes crop lightly for two or three years. Late frost can kill the flowers. A lone plant of a variety that needs a partner sets little.
Wilting, scorched leaves in summer
- Drought
Shallow roots suffer fast in dry weather. Water deeply and mulch.
More problems with blueberries
Common pests
Birds
The biggest threat to the crop. Net the bushes as soon as the first fruit turns blue, ideally on a frame that holds the net above the plants, or grow them in a fruit cage. Noise scarers soon stop working.
Spotted wing drosophila
Tiny flies whose larvae feed inside the fruit, worst on later varieties. Pick berries as soon as they are ripe and chill or freeze them straight away.
Vine weevil
Mainly on pot-grown plants. Adults notch the leaves; the grubs eat the roots. Pick out grubs by hand or use nematodes.
Rabbits, deer and voles
Rabbits and deer eat twigs under snow; voles nest in deep mulch. Fence where they are a problem.
Common diseases
Mummy berry
A fungal disease that shrivels berries into hard, grey ‘mummies’, worst after a rainy spring. Clear fallen mummified berries.
Powdery mildew
A white coating on leaves when conditions are too dry or too wet. It rarely harms the plant much; remove and destroy affected shoots.
Phytophthora root rot
Sections of the plant die in midsummer and whole plants decline over time, worse in wet, heavy soil (OSU). On poorly drained ground, plant on a raised ridge or bed.
Harvest & Use
Pick only fully ripe berries, every few days, and eat them fresh or freeze them.
Harvesting blueberries
Blueberries ripen from midsummer into early autumn, depending on variety. Each cluster ripens gradually over several weeks.
Wait for full ripeness. Berries turn blue a few days before they are fully ripe, often with a slight reddish tinge still at the stalk end. Waiting those extra days gives sweeter, bigger fruit (UNH).
How. Gently pick the deepest blue berries and leave greener ones to ripen. Pick every few days, and pick every ripe berry each time.
When to expect crops. It takes two or three years before you get large harvests, and a bush keeps improving for years after.
- Wait a few days after the berries turn blue.
- Pick every few days, all the ripe ones.
- Big crops from about year three.
Storing and using blueberries
Blueberries are best eaten fresh. Chill them promptly and don’t wash them until you eat them, or they mould; use within about a week (UMN).
Freezing. They freeze very well, loose on trays and then bagged. Frozen berries are good for baking, smoothies, jams and compotes.
Propagation
Take softwood cuttings in spring or semi-ripe cuttings in summer.
Propagating blueberries
Cuttings are the reliable way to make more of a variety you like. Take them from young, non-flowering shoots: softwood cuttings in spring, or semi-ripe cuttings in summer (Gardeners’ World).
Seed from the berries is possible, but slow and uncertain: it takes years to make a small bush, and the plant won’t match the variety you ate.
More to Explore
Quick answers, guides that pair well with blueberries, and the sources behind this one.
Frequently asked questions
What soil do blueberries need?
Acid soil, about pH 4.5 to 5.5, moist but free-draining and rich in organic matter. See acid soil.
Can I grow blueberries in a pot?
Yes, and it is the answer on alkaline soil. See planting blueberries in pots.
Do I need two blueberry bushes?
Most varieties will, but some, such as ‘Brigitta’, need a partner, and two or three varieties flowering together give bigger crops and berries.
Why are my blueberry leaves turning yellow?
Often the soil isn’t acid enough; it can also be a lack of nitrogen. See common problems.
Should I water blueberries with tap water?
Rainwater is better: tap water is usually alkaline and slowly raises the pH.
How long until blueberries fruit?
Pick off the flowers for the first two years; large harvests follow from about year three.
When should I prune blueberries?
In late winter while dormant; established bushes every year. See pruning.
How do I keep birds off blueberries?
Net the bushes as soon as the first berries turn blue, or grow them in a fruit cage.
Are coffee grounds good for blueberries?
Not as a pH fix: they aren’t reliably acid. Use elemental sulfur.
When are blueberries ripe?
A few days after they turn fully blue. See harvesting.
Related guides
Sources
- How to grow blueberries (opens in a new tab) Royal Horticultural Society
- Growing blueberries in the home garden (opens in a new tab) University of Minnesota Extension
- Growing fruit: highbush blueberries (opens in a new tab) University of New Hampshire Extension
- Growing and caring for blueberries (opens in a new tab) University of Illinois Extension
- Growing blueberries in your home garden (EC 1304) (opens in a new tab) Oregon State University Extension Service
- How to grow blueberries (opens in a new tab) BBC Gardeners’ World