Shrub · Rosaceae
Blackberry
Rubus fruticosus
Give it full sun and room to ramble, and a blackberry hands you buckets of fruit for years.
Full sun
Every 3–7 days
USDA 5–9
3–10 ft · 0.9–3 m
Overview
Blackberries are one of the most generous fruits a beginner can grow. The plant is a bramble in the rose family, throwing up long arching canes that root wherever they touch the ground. Plant one and, left to its own devices, it will happily try to take over a corner of the garden.
What makes a blackberry tick is the way its canes work in pairs of years. A cane spends its first season as a leafy primocane, then fruits the next year as a floricane before it dies back. Once you see that rhythm, the pruning makes sense and the harvest stays steady.
These are tough, cold-hardy plants that crop heavily for little fuss. Give them sun, decent soil, and a yearly tidy-up, and you will be picking warm berries by the handful in midsummer. The main thing to plan for is space, since a happy patch spreads fast.
Care
The short version: full sun, deep and well-drained soil, and about an inch or two of water a week. Prune out the old fruited canes each year and give the plant plenty of room to spread.
Light
Blackberries crop best in full sun, ideally six or more hours a day. They will take a little afternoon shade, but the more sun they get, the sweeter and heavier the fruit.
Water
Keep the soil evenly moist but never waterlogged. That means about 1 to 2 inches of water a week, and more while the plant is flowering and swelling its fruit, when a dry spell can leave you with small, crumbly berries.
Soil
Plant in deep, well-drained loam with plenty of organic matter worked in. A pH between 5.5 and 7.0 suits them, and the better the drainage, the less you fight root and cane disease.
Temperature
Blackberries are tough, riding out winters down to -4°F (-20°C) and summers up to 95°F (35°C). They suit hardiness zones 5 through 9, so most gardeners can grow them without protection.
Humidity
Average outdoor humidity of 40% to 70% is fine. Air movement matters more than the number, since still, damp air around crowded canes is what lets rust and blight take hold.
Feeding
Feed once in early spring as growth starts back up, using a balanced 10-10-10 or a nitrogen-rich complete fertilizer. One seasonal feeding is usually enough to carry the canes through fruiting.
Pruning
The canes are biennial, so pruning follows the two-year cycle. Cut spent floricanes to the ground after harvest, tip-prune the primocanes in summer to push out fruiting laterals, and thin the patch to a handful of strong canes.
Repotting
Blackberries are grown in the ground rather than pots, so they rarely need repotting. If you do keep one in a container, move it on when roots circle the pot or cane growth stalls and the soil dries out fast.
Size & spacing
Canes reach 3 to 10 feet (90 cm to 3 m) tall and spread just as wide. Give each plant that much room to arch and sucker, both for airflow and to keep the patch from swallowing its neighbors.
When to plant
Blackberries go in while they are still dormant. Set out bare-root or potted canes in late winter to early spring once hard frosts have passed, watch for blooms in late spring, and pick ripe berries through the heat of July and August.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Set out dormant bare-root or container canes in late winter to early spring after danger of hard frost has passed.
- Harvest: Blooms in late spring; berries ripen mid to late summer (typically July to August).
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Most blackberry trouble shows up on the canes or the fruit, and a quick walk through the patch catches it early. Match what you see below, then act before a fungus or a mite settles in for good.
Bright orange powder on the undersides of the leaves
This is orange rust, a fungus that lives inside the whole plant rather than just on the surface. Once a cane shows the orange spores, the plant will never recover and stays a source of infection. Dig out the entire plant, roots and all, and never compost it.
Fix:
- Dig out and destroy entire infected plants including roots
- Do not compost infected material
Dark cracking lesions on the canes with dieback above
Cane blight and anthracnose are fungi that settle into wounds and girdle the cane, so everything above the spot wilts and dies. Prune the affected canes out well below the lesion and thin the rest so air moves freely. Cut only in dry weather, since fresh wounds in the wet are how the fungus gets in.
Fix:
- Prune out and destroy affected canes below the lesion
- Thin canes to improve air circulation
Crumbly, lopsided berries with hard red bumps
When only some of the tiny druplets swell and others stay hard and red, the cause is usually poor pollination, though redberry mite or a virus can do the same. Draw in more bees with flowers nearby, and treat the canes with horticultural oil if mites are the problem. Pull and replace any plant you suspect carries a virus.
Fix:
- Encourage pollinator activity near the planting
- Apply horticultural oil to manage mites
Toxicity
There is no poison to worry about here. The berries, leaves, and canes are safe for people, pets, and livestock alike, and the fruit is a treat for all of them. The one real hazard is physical, since most blackberries carry sharp thorns that scratch skin and snag fur.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Nothing in the plant will poison a cat. The only thing to watch is the thorns, which can scratch a curious paw or nose.
Dogs None
A dog can eat the ripe berries without harm, and many love them. Wolfing down a big pile may bring on a loose stomach, so keep treats modest.
Horses Safe
Horses graze blackberry leaves and fruit with no ill effect. The sharp canes are the real concern, since they can cut a soft muzzle.
Rabbits Safe
The leaves and fruit are safe, and rabbits enjoy nibbling the foliage. Offer berries sparingly because the sugar is rich for a small animal.
Livestock Safe
Cattle, goats, and sheep browse brambles freely, and goats will happily clear a thicket. None of it is poisonous to them.
Birds Safe
Wild birds flock to ripe blackberries and spread the seeds far and wide. The fruit poses no danger at all.
People Safe
Blackberries are a well-loved fruit, eaten fresh or cooked, and the young leaves have long been brewed as tea. Mind the thorns when you pick.
The main hazard is physical rather than chemical: most wild and cultivated blackberries bear sharp thorns (prickles) along the canes that can scratch skin or injure pets, though thornless cultivars such as 'Navaho' and 'Apache' exist and are safer to handle.
Varieties
Hundreds of blackberries exist, split mainly into upright and trailing types. These three are worth knowing, including a couple bred to drop the thorns.
Navaho
A thornless, upright type from the University of Arkansas and USDA breeding program that carries sweet, firm berries on canes you can handle bare-handed.
Marionberry
A trailing blackberry bred at Oregon State University by crossing Chehalem with Olallie, and a longtime favorite across the Pacific Northwest.
Apache
Another thornless, upright cultivar that stands out for very large fruit and strong resistance to disease.
Companions
Blackberries do best kept apart from their own relatives and from the nightshade family, since both trade diseases that brambles are prone to.
Keep apart
Raspberry and other Rubus: Planting close to other brambles spreads shared diseases such as orange rust and viruses.
Tomato, potato, and other Solanaceae: They share susceptibility to Verticillium wilt, so avoid planting blackberries where solanaceous crops recently grew.
How to propagate
Blackberries are easy to multiply, and a single plant gives you several ways to do it. Layering and division take almost no skill, while cuttings ask for a bit more patience.
LayeringEasy
Late summer · Roots form in 6 to 8 weeks; transplant the following spring
Trailing types almost layer themselves. In late summer, bend a cane tip down until it touches bare soil and pin it in place, and roots take hold in about 6 to 8 weeks. Leave the new plant attached over winter and lift it the following spring.
DivisionEasy
Late winter to early spring while dormant · One growing season
An established clump throws up rooted suckers around its base. Dig these up or split a crown in late winter to early spring while the plant is dormant, then replant straight away. Give each division a full growing season to settle in before you expect a real crop.
Stem cuttingsModerate
Winter for root cuttings or summer for softwood cuttings · Several weeks to a few months
Cuttings take a steadier hand than the other methods. Take root cuttings in winter or softwood cuttings in summer, and expect rooting to run anywhere from several weeks to a few months. Root cuttings are the standard way nurseries bulk up the upright kinds.
Myths
Blackberries and raspberries are the same fruit since both are brambles.
Both belong to the genus Rubus, so the confusion is fair, but the fruit tells them apart. A picked blackberry keeps its white core, the little plug called the receptacle, while a raspberry slips off and leaves that core behind on the plant, which is why a raspberry is hollow inside.
Every blackberry has thorns.
Thorns are common, but they are no longer the rule. Many modern cultivars like Navaho and Apache are fully thornless and crop just as well, so you can grow and pick blackberries without ever drawing blood.