BLUE SPRINGS, Mo.-Upright blackberries need dormant pruning to ensure adequate berry size, promote vigorous canes for next year’s growth and keep the fruit off the ground, says a University of Missouri Extension horticulture specialist.
“In addition to pruning, older plantings of upright blackberries may require thinning in order to keep the planting within reasonable bounds in the landscape,” said Marlin Bates. “When thinning mature plantings, consider reserving healthy plants for distribution to friends and family.”
Dormant pruning consists of reducing lateral shoot growth to a length of 12-15 inches, Bates said. “This reduces the number of flower buds that will develop, but results in larger fruits and ensures that the plant can support the expected crop load.”
Unlike trailing blackberry plants, which produce new shoots only from the crown, upright blackberries produce new shoots from both the crown and the surrounding root system, he said. An ideal upright blackberry row should be 12-18 inches wide. During dormant pruning, remove any canes that develop outside of the row.
“If the blackberry planting is healthy, the canes that require removal can be used to expand the planting or potted up to be shared,” Bates said.
When the crown region of upright blackberries begins to become too dense with shoots, you can divide the entire plant. “The 12- to 18-inch row of blackberry canes should have a density of about six to eight strong canes per linear foot,” he said. “Dividing the crown of established blackberry plants is a good way to establish the proper density of the planting. Again, the plant portion that is removed from the row can be used to expand the planting or given away as long as the plant is healthy.”
For more information on pruning and dividing bramble plantings, see MU Extension publication G6000, “Pruning Raspberries, Blackberries and Gooseberries,” available for purchase or free download at http://bit.ly/MUExtG6000. Browse or search other MU Extension publications at http://extension.missouri.edu/publications.
Please stop by the Madison County Extension Center for information on gardening, flowers, blackberries and more or give Brenda or Celeste a call at 573-783-3303.
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