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Blackberries growing on a bush.

If you have only picked and eaten the wild blackberries that grow along fencerows, you are missing out on a treat. There are many different cultivated blackberry plants that are much larger and more productive than the wild plants.

Anatomy

The root systems of blackberry plants are perennial (can live for many years), while the canes (above ground stems) are biennial (live for two years). When discussing canes, there are two terms that people need to understand; primocanes and floricanes.

Primocanes are first year canes. They grow and set flower buds, but usually do not bloom the first year. However, there are some primocane blackberry varieties available on the market. In the second year of growth, the name of these canes change to floricane. In this second year, the floricanes, will bloom and set fruit. After fruiting, they will soon begin to wilt and die. While the floricanes are flowering and fruiting, new primocanes begin to grow.

Planting Practices

Blackberry plants grow and fruit best when they are planted in full sun. There are also several other practices to remember when planting blackberries. Growers should:

  • irrigate in times of drought
  • train and prune correctly
  • manage weeds
  • make sure the soil has good internal drainage

The soil pH should be in the range of 6.0 to 6.5. A soil test will determine the pH and provide information on nutrients that may be lacking.

Growth

The growth habit of blackberries can be erect, semi-erect, and trailing. Trailing and semi-erect plants require a trellis, but the erect plants do not. Erect plants are maintained at about 3 feet tall. If grown any taller, wind could blown them over. Beginning in the spring, allow the primocanes to grow about 3 1/2 feet tall before cutting the shoots back to about 3 feet. Lateral (side) branches will grow and can become quite long. During the winter, prune back these branches to about 12 to 18 inches long.

Spacing

If a grower has more than one row of blackberries, the rows should be spaced a minimum of 12 feet apart. In-row spacing of the plants depends on the growth habit of the plant and if they are trellised or non trellised.

Trailing blackberry plants should be spaced about 10 feet apart in the row. This allows the plants to grow about 5 feet in either direction. Spacing for erect plants, not trellised and maintained about 3 feet tall, would be about 3 feet apart. If the erect plants are trellised, it is common to see them 5 to 6 feet apart.

Trellising

While not required, it is common to see erect plants maintained on a trellis along with the trailing and semi-erect varieties. Growing erect plants with a trellis allows the plant to be maintained higher than 3 feet and the lateral shoots can be much longer than 18 inches. This also makes picking berries from these plants easier. The trellis keeps the taller grown, erect plants from being blown over by the wind or from laying down due to a heavy fruit load.

Remember, blackberry canes will need to be tied to the trellis as they grow. It is common to see a trellis with the top wire about 5 feet above the ground and another about 3 ½ feet above the ground.  Another common three wire spacing is installing the top wire at 5 feet above the ground, the bottom wire at 24 inches above the ground, and installing the middle wire about 18 inches above the bottom wire. These wire spacings are only examples, and several other trellising systems are used by growers.

More Information

For more information on blackberry plants, contact you county Extension office, or visit www.aces.edu.

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