Trailing blackberry varieties such as 'Siskiyou' and 'Chester Thornless' are popular for their large-sized fruits and heavy production. But little commercial production of trailing blackberries takes place in areas colder than USDA zone 6 because of their lack of winter hardiness. A new technique developed at the Agricultural Research Service in Kearneysville, West Virginia, may help expand the growing range of these fruits.
Blackberries are normally grown on trellises to keep the canes erect. Researchers created a rotating, cross-arm trellis system that allows growers to bend the canes to the ground in winter. Then the canes can be covered with insulation, such as a floating row cover or plastic sheeting.
Trials on protected and non-protected canes of 'Siskiyou' blackberries revealed that protected canes produced 3 to 5 times more fruit than non-protected canes and produced three weeks earlier. This technique may allow gardeners in areas colder than USDA zone 6 to consistently produce a good crop of trailing blackberries.