How to Grow and Care for Blackberries

Blackberries are native to the United States and thrive in temperate climates, providing growers with plump berries throughout the summer. Blackberry plants are easy to grow, thriving in sunny conditions and well-drained, acidic soil. They are also easy to propagate, increasing your overall fruit yield.

How to Plant Blackberries

When to Plant

Blackberries can really be planted any time of the year in areas where they are hardy, but they should preferably be planted when they're dormant. Blackberry plants that are planted in winter will have lots of time to settle into the ground before the growing season begins in spring.

Selecting a Planting Site

Choose a site that gets full sun, which means at least six hours of direct, unfiltered sunlight. More sunlight is better. If necessary, amend the soil before planting so that it is rich, well-draining, and slightly acidic.

If you have wild blackberries growing, do not plant your cultivated blackberries nearby in order to avoid the spread of plant diseases.

Spacing, Depth, and Support

Blackberry plants should be spaced five to six feet apart; if planting in rows, space the rows five to eight feet apart. Blackberries should be planted relatively shallow—about one inch deeper than they were growing in the nursery pot.

Trailing varieties of blackberries should have a trellis or other form of support to secure the canes.

Blackberry Plant Care

Light

Sites with full sun are best for productive blackberry bushes. Some afternoon shade is tolerated, especially in areas with hot summers.

Soil

Careful site selection will ensure a long life for your blackberries, which usually live for about a decade with proper care. The ideal soil is slightly acidic with good drainage; these plants do not do well in clay soil. An elevated site or raised beds will not only help drainage but will also prevent late spring frosts from damaging flower buds. Remove all weeds that might draw nutrients or water away from your blackberries, as their shallow roots are susceptible to this competition.

Keep a good layer of mulch over the root zone at all times. This will feed the plants, conserve water moisture, and keep weeds down.

Water

Blackberries need moderate amounts of water, around one inch per week provided either by rainfall or from ground-level irrigation. Blackberries do not fare well in wet soils.

Temperature and Humidity

Blackberries require a period of cold dormancy to germinate, but because of their shallow root systems, they don't do well in areas where temperatures go below zero degrees routinely. Roughly zones 5 to 9 provide the best environment for blackberries, depending on the cultivar.

Cold winter temperatures combined with wet spring soils may lead to plant death. The reverse environment of hot, dry winds is also unfavorable for blackberry growing and may result in stunted, seedy fruits.

Fertilizer

Fertilize your blackberries in the spring when plants are emerging from dormancy, using a balanced 10-10-10 formula. Fertilize plants again in the fall with an application of manure and compost, which will also suppress weeds and improve soil tilth.

Pollination

Blackberries are self-pollinating, so you will not need multiple plants for fruit production. Bees and other insects will assist in pollination. If growing blackberries indoors, you will have to manually assist in pollinating. To do so, take a Q-tip and gently touch it to each flower on the plant, spreading pollen. Do this for multiple days until the flowers begin to turn brown.

Types of Blackberries

Blackberries are usually categorized according to their growth habit: erect thorny, erect thornless, and trailing thornless. Here are a few popular cultivars:

• 'Shawnee': is resistant to cold, and has self-supporting thorny canes.
• Natchez': is thornless and erect and will form a hedgerow as it spreads by suckers.
• 'Chester' and 'Triple Crown': are both semi-erect thornless varieties that grow as a clump, and benefit from a trellis.
• 'Prime-Ark Traveler': produces fruit on new and old canes throughout the season.

Blackberries vs. Raspberries

Both blackberries and raspberries belong to the Rubus genus. Blackberry and raspberry plants look very similar—both featuring thorny canes and compound leaves with toothed edges in groups of three or five. One key difference between the fruits of blackberries and raspberries is the way the fruits are formed. The tiny globes of the fruits, called drupelets, are attached to a white core in blackberries. Raspberries, including black raspberries, form drupelets with a hollow core.

Harvesting Blackberries

Once the blackberries begin to ripen, plan to harvest all ripe berries every couple of days. Berries that are ripe will be black and plump. Gently pluck the ripe berries from the vine, and, unlike with raspberries, leave the central plug inside the blackberry.

Be sure to keep harvested berries cool, ideally placing them in the fridge but definitely at least keeping them in the shade or indoors.

How to Grow Blackberries in Pots

If you have limited space, you may want to try growing blackberries vertically in pots. Be sure you can place your potted blackberry plant in a location with full sun and that the soil in the pot is particularly well-draining.

When choosing a container, pick a large pot that's a couple of feet wide, ideally wider, and with one or multiple drainage holes. Find a fitting trellis that will allow your blackberry plant to vine upwards. Otherwise, treat this plant as you would a blackberry plant in the ground.

Pruning

Blackberry roots are perennial but the canes are biennial. This means that second-year canes that have produced their fruit need to be trimmed away after harvesting.

For an established shrub, new canes that haven't yet fruited should be tip-pruned to about three feet in summer. This will cause the new canes to branch out, maximizing the fruit produced. Once these canes produce fruit, they should be removed to the ground immediately after the fruit harvest.

In early spring before new growth has started, remove any canes damaged by winter, and thin out the remaining canes to the four or five strongest canes.

Propagating Blackberries

It's easy to propagate blackberry plants from stem cuttings. Cut a 4-inch piece from the end of the stem in late spring when temperatures are mild and rainfall is plenty. Plant it in the soil, and keep it moist. Roots will form in two to four weeks. These newly started plants can be planted in the fall, or you can keep them in a sheltered location and plant them the following spring.

How to Grow Blackberries from Seed

Usually, small blackberry bushes or blackberry vines are purchased and planted, though blackberries can be started from seed.

1. Gather small pots or seed trays and fill them with seed-starting mix.
2. Sow seeds at about 1/4 inch deep and sprinkle them lightly with more seed-starting mix.
3. Gently water the seeds without displacing them, and keep the soil moist until germination.
4. Keep germinating seeds in a warm spot around room temperature.
5. Wait until the seedlings have one or two sets of true leaves, and then move them into bigger pots with well-draining soil.
6. Transplant directly into the ground in spring once the last frost has passed.

Overwintering

Blackberries planted in USDA hardiness zones 5-9 should survive the winter just fine, but it's still a good idea to provide some assistance.

If your blackberries are planted directly into the ground, add mulch or straw around the base, which will keep the plants warmer and offer some protection from the winter elements. Potted blackberries should be moved indoors. At the very least, place potted blackberries along the outside walls of the home to keep them slightly warmer.

Common Pests and Plant Diseases

Blackberries are prone to anthracnose, stem blight, and crown gall. Prevent disease by purchasing disease-free plant stock from reputable nurseries and by planting your blackberries away from areas with wild brambles, which may carry these diseases.

Insect pests include stink bugs and raspberry crown borers. Keeping your plants healthy and vigorous will make them less attractive to insect attack.

Blackberries are sometimes afflicted by viral diseases. Raspberry bushy dwarf virus and blackberry calico virus both cause bright yellow splotches to appear on leaves. Affected plants will need to be removed and destroyed.