How to Grow and Care for Blackberries

Blackberries produce juicy berries in the summer or fall. Although these hardy perennial plants are native to many parts of the world, blackberries have been mostly domesticated in North America and Europe. The blackberry cultivars sold in the nursery trade today are the result of extensive and ongoing blackberry breeding. While the fruit color of blackberries is consistently black, the fruit size and shape, yield, growth habit of the plant, and harvest season vary between cultivars.

Blackberry plants are easy to grow and long-lived with a lifespan of 15 to 40 years.

How to Plant Blackberries

When to Plant

Blackberries are best planted in the early spring while they are dormant.

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.

Any wild brambles or wild blackberries within 1,000 feet of distance are a potential source of diseases and should be destroyed before planting.

Spacing, Depth, and Support

Blackberry plants should be spaced 5 to 6 feet apart; if planting in rows, space the rows 5 to 8 feet apart. Blackberries should be planted relatively shallow, about 1 to 2 inches below the soil.

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

The soil should be slightly acidic (pH between 5.6 and 6.5) with good drainage. If the soil is wet or has a high clay content, amend it with organic matter before planting.

Keep a 1- to 2-inch layer of mulch over the root zone at all times to preserve soil moisture and suppress weeds.

Water

Blackberries need moderate amounts of water, around 1 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 just after the harvest in the late summer or fall.

Pollination

Blackberries are self-pollinating, so you will not need multiple plants for fruit production. Bees and other insects will assist in pollination.

Types of Blackberries

Blackberries are categorized according to their growth habit (erect or trailing), thornless or thorny, and harvest time (summer-bearing or fall-bearing).

Popular blackberry cultivars include:

• 'Shawnee' has self-supporting thorny canes. The berries ripen over a long period of five weeks during June and July.
• '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 Freedom' bears fruit on new and old thornless canes throughout the season.
• 'Prime-Ark Traveler' is very similar to 'Prime Ark Freedom' but the berries are firmer so they hold up better in shipping and they ripen about two weeks later.
• 'Ouachita' is a thornless erect blackberry. It only grows 4 to 5 feet tall and 3 to 4 feet wide, which makes it a good fit for suburban and urban spaces. It has good heat tolerance.
• 'Sweet Ark Ponca' is a thornless, erect cultivar whose firm. low-acid berries stand out by their very sweet flavor.

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 place your potted blackberry plant in a location with full sun and that the soil in the pot is well-draining.

When choosing a container, pick a large pot that's 2 feet wide, ideally wider, and with one or multiple drainage holes. Find a fitting trellis to support the lateral growth of the canes.

Repot the plants to a container one size up and with fresh soil when the roots have outgrown the container, or at least every two years to refresh the soil.

Pruning

Blackberry roots are perennial but the canes are biennial. First-year and second-year canes are pruned differently. New canes that haven't yet fruited should be tip-pruned in the spring to about 3 feet. This will cause the new canes to branch out, maximizing fruit production. Immediately after the harvest, cut the second-year fruiting canes back to ground level.

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 of the strongest canes per foot.

Propagating Blackberries

The easiest way to propagate blackberries is to dig up one of the suckers that grow in great numbers at the base of the plant. Plant it in a pot large enough to fit the roots or directly in a new location and keep it evenly moist until it has grown some new foliage.

Overwintering

Blackberries planted in USDA hardiness zones 5-9 should survive the winter just fine, but it's still a good idea add mulch or straw around the base to insulate the roots.

Potted blackberries should be moved to an unheated garage or shed, buried in the ground, or planted inside an insulating silo.

Common Pests and Plant Diseases

Blackberries are prone to anthracnose, stem blight, and crown gall. Only purchase plant stock from reputable nurseries and plant your blackberries away from areas with wild brambles.

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

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 need to be removed and destroyed.

From: thespruce