Friday, November 25, 2011

Growing Blackberries

Gone are the summer days when you could carry your metal pail along fence rows and country roads to pick blackberries. Country roads are becoming suburban. Traffic is increasing. Fences are disappearing. DOTs are spraying herbicides to keep the brush down.

The good news is that blackberry cultivars have been developed that are superior to the wild ones, and they can be easily grown in your own backyard. They don't take long to bear fruit, either. Berries are produced the second year.

Blackberries can be grouped into three types according to their growth habit:
  1. Trailing, which produce thin, weak canes, and require support;
  2. Semi-erect, which produce stronger canes, but still require support;
  3. Erect, which produce strong canes, and do not require support.
Within these groups are thornless and thorny cultivars.

When blackberry crowns and roots are established, they send up shoots which are called primocanes. No fruit is produced on these the first year. The second year, shoots are produced from the primocanes. These secondary shoots are called floricanes. The floricanes are the ones that bear fruit. After the floricanes bear fruit, they die. In 2004, the University of Arkansas began releasing new “everbearing” cultivars that bear fruit on new primocanes in fall.

Trailing and semi-erect blackberries usually produce primocanes from the crowns. Erect
blackberries produce primocanes from crowns and roots. One practical result is that trailing and semi-erect blackberries tend to stay in the garden row, whereas erect blackberries are not so easily confined.

Consultation with your local Cooperative Extension Service is essential for choosing cultivars that are suitable for your area. Blackberries are self-fruitful, so it is not necessary to plant more than one cultivar, unless you wish to extend the harvest season by planting early and late-season bearers.

The following, listed alphabetically, are a few to consider:

Arapaho. Released by the University of Arkansas in 1993, it is erect and thornless. The picking period is short. Fruit is good quality, medium size, short, cone-shaped, glossy black, and stores well.

Black Satin. Thornless, and semi-erect. When ripe, a few portions of the berry remain red.

Cherokee. Released by the University of Arkansas in 1974, the plants are vigorous, erect, and thorny. Fruit is large and firm, with very good flavor.

Chester Thornless. Released by USDA Small Fruit Breeding Program and Southern Illinois University in 1985, fruits are large, firm, and ripen late season. Canes are semi-erect.

Cheyenne. Released by the University of Arkansas in 1977, fruits are large and firm. Canes are vigorous, erect and moderately thorny.

Choctaw. Released by the University of Arkansas in 1989, fruits are medium size. Seeds are small. Plants are vigorous, erect, and thorny.

Dirksen Thornless. Released by the USDA, fruits are large and sweet. Plants are semi-erect and very hardy.

Hull. Released by USDA and Illinois Agricultural Experiment Station in 1981, the plants are thornless and semi-erect. Fruits are large.

Illini-Hardy. Released in 1988, the plant is very cold hardy. Fruits are medium size with good flavor. Plants are vigorous, erect and thorny.

Kiowa. Released by the University of Arkansas in 1996, the canes are vigorous, erect and very thorny. Fruit is very large fruit and ripen over a long season.

Navaho. Released by the University of Arkansas in 1988, berries are medium size and good quality. Canes are erect and thornless.

Prime-Jan. Released by the University of Arkansas in 2004, berries are large size, good quality. Canes are erect and thorny.

Prime-Jim. Released by the University of Arkansas in 2004, berries are medium size and good quality. Canes are erect and thorny.

Shawnee. Released by the University of Arkansas in 1985, fruits are large and good quality. Plants are hardy and very productive. Excellent for backyard gardens.

Triple Crown. Released by the in USDA 1996, fruits are very large and excellent quality. Ripens late. Canes are semi-erect.

Blackberries are generally hardy in USDA climate zones 5 through 10. Those developed and released by university breeding programs in Northern states are best suited for those areas.

Blackberries require full sun, well-drained soil that is high in organic matter with pH between 6.0 and 6.5. Where drainage is a problem, blackberries should be grown in raised beds.

Ideal planting sites should be protected from spring frosts and strong winds. Good air circulation is essential for avoiding diseases. To avoid diseases, do not plant blackberries near tomatoes, potatoes, peppers and similar crops of the Solanaceae family. Similarly, avoid sites where other fruits have been grown. Because wild blackberries can host diseases, do not plant cultivated blackberries nearby.

Before planting, take a soil sample to your nearest Cooperative Extension Service office for analysis. Follow the recommendations. Begin preparing the site by spraying weeds with glyphosate herbicide. When weeds have died, till the area, wait for dormant weed seeds to germinate, then spray the area again with glyphosate.

Blackberry plantings can be started from container-grown plants, bare-root plants, bare-root crowns or root cuttings. Bare-root plants are dug from nursery rows, soil removed, and partially trimmed. They may produce a few fruit the first year. Bare-root crowns are dug from nursery rows, soil removed, canes removed and roots trimmed. No fruit will be produced the first year. Root cuttings are sections of roots about 6 inches long and the diameter of a pencil. Again, no fruit will be produced the first year. Cuttings are most economical to purchase. Container-grown plants may be available year-around. Bare root plants, crowns and root cuttings are normally available from late fall through early spring.

Fall through early spring planting is preferable. Keep plants moist after arrival. If roots are dry, soak them in water overnight before planting.

Plant spacing varies according to the type of plant and training method. Trailing and semi-erect plants should be planted about 6 feet apart in rows to allow for training their long canes on trellises. Erect blackberries should be planted 3 feet apart in rows. Root cuttings should be planted 2 feet apart in rows. Primocanes of erect blackberries will be produced from the roots as they spread. Blackberry rows should be 10 to 12 feet apart to allow for easy maintenance.

Remove container-grown blackberries from their pots and plant with the top of the root ball at the same level as surrounding soil. Plant bare-root plants and bare-root crowns at the same depth that they grew in the nursery row. This can be determined by observing a difference in color and texture around the crown. The area below soil level will be lighter color. Root cuttings should be planted in a shallow trench about 3 inches deep.

Weeds must be controlled from the beginning. Small gardens may be hand-weeded, taking care to avoid harming tender young canes. Heavy applications of mulch are effective for controlling weeds provided that water drainage is not impeded. Larger gardens may require herbicides. Contact your local Cooperative Extension Service for recommendations. Always follow label instructions.

Semi-erect and trailing blackberries will require trellising, however the trellises need not be constructed the first year. Trellises must be constructed before the second growing season.

Many trellis designs have been developed. The simplest method is to drive a sturdy post into ground near the plant crown, then gather the canes and tie them to the post. This, however, is not the best for optimal fruit production.

A simple two-wire trellis may be the easiest for the backyard fruit grower to build. Determine the desired length of the blackberry row. I recommend it be no shorter than 36 feet.

Begin with braced end-posts at the each end of the row. Use 8 foot long pressure treated fence posts. Install them 2 feet deep and 8 feet apart. Secure an 8 foot long pressure-treated cross post between them. If the row is no longer than 36 feet, two 11-gauge wires may be strung between the end posts. The bottom wire should be 3 feet from ground level. The top wire should be 2 feet above the lower wire.

If the blackberry row is longer than 36 feet, steel fence posts may be driven into the ground to support the wires. The steel fence posts may be as far as 20 feet apart. After the trellis is constructed, the canes should be tied individually to the wires with baling string or plastic tape. Many growers attach the canes to the wires in a fan-shaped configuration. After attaching them, lateral branches may be trimmed to 12 inches long.

Expect a small harvest the first year. After the berries have been picked, remove the old canes. Take care when pruning to avoid damaging new ones. During the growing season, short, weak canes should be removed to put more of the plants resources into producing longer, robust canes. Canes that grow taller than the top wire can be trimmed at the ends to encourage lateral branching.

Erect blackberries do not need trellising, however a shorter trellis 3 feet high may be constructed to support floricanes with heavy crops. The canes shouldn't need to be attached to the trellis, but a gardener may wish to gently weave them between the wires. When the canes reach the top wire, they can topped with a hedge trimmer to encourage lateral branching. As with trailing and semi-erect blackberries, old canes should be removed after berries are harvested.

Blackberries are shallow-rooted, so the top 6 inches of soil should remain moist, especially during fruit production. Combined rainfall and irrigation should amount to 1 inch of water per week. Mulch applied to a depth of 3 or 4 inches conserve moisture and reduce the amount of water needed.

The soil analysis results obtained from your Cooperative Extension Service will indicate the type and amount of fertilizer needed.

Insects and diseases can damage blackberries, but a proper planting site and garden hygiene can reduce problems.
  1. Purchase only disease-free plants;
  2. I mentioned before that wild blackberries should not be present. If they appear, get rid of them;
  3. Remove diseased and insect-infested plants;
  4. Prune and remove old canes from the garden soon after harvest;
  5. Burn the removed debris.
Blackberries are pollinated by honey bees, so care must be taken to avoid insecticide use anywhere in the garden during bloom period.

Blackberries should be picked at least twice weekly. Pick only when fully ripe. Picking them in the morning will maintain fruit quality. Because the fruit is soft, picking and storage containers should be no deeper than 2 inches. Refrigerate soon after harvesting.

John J Marshall
John also blogs at

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