A SIMPLE WINTER PROTECTION SYSTEM FOR BLACKBERRIES

Authors: Takeda, Fumiomi; HANDLEY, DAVID - UNIV OF MAINE, EXT SPECIA

Submitted to: Proceedings of the North American Bramble Growers Association Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: 1/30/2006
Publication Date: 2/24/2006
Citation: Takeda, F., Handley, D. 2006. A simple winter protection system for blackberries. Proceedings of the North American Bramble Growers Association Annual Meeting. Pages 21-26.

Interpretive Summary: Little commercial blackberry production exists in areas with severe winters (minimum winter temperatures below 0 degrees F) and short growing seasons. In this study, we evaluated the combination of simple cultural practices, a modified rotatable cross-arm (RCA) trellis system, and covering plants with insulation material in winter to overcome the lack of cold hardiness in trailing (‘Siskiyou’ and ‘Boysenberry’) blackberries that have been established at Kearneysville, WV (39 degrees Latitude N). RCA trellis assembly has an upright post and a long cross-arm with a mechanism at the top of the post that permits the cross-arm to be pivoted and rotated as much as 22 degrees. A special cane training practice spatially separates primocanes and floricanes. Alter tying canes to trellis wires and rotating the cross-arms to below horizontal, tied canes are close to the ground, allowing them to be covered with protective materials such as floating row cover (FRC) and polyethylene plastic (PE) during the winter months. Covers are removed in the early spring and canes remain in the horizontal orientation until bloom, encouraging flowering laterals grow upright. After bloom, the cross-arm is rotated to slightly beyond vertical. This positions the fruit on one side of the row and improves harvest efficiency. In January and February 2005, the daily minimum temperatures under the FRC+PE cover treatment were about 6 degrees F higher than in the open. The FRC+PE cover also provided protection against the wind. Tissue damage in trailing blackberries protected with a FRC+PE cover was significantly less than for unprotected plants. ‘Siskiyou’ plants in FRC+PE covered plots produced 3 to 5 times more fruit than plants in the open. Harvesting of ‘Siskiyou’ fruit occurred during the red raspberry harvest season or two to three weeks earlier than that for ‘Chester Thornless’ eastern thornless blackberry. Our findings suggest that trailing blackberries that lack winter hardiness may grow satisfactorily and produce fruit by mitigating the adverse effect of low temperatures and winds with our unique trellis system and winter protection system. RCA trellis system is amenable to cane manipulation and placement of winter protection material. The trailing blackberries could be included for fruit production in the eastern United States if practical cultural techniques for improving their winter survival become available. With addition of cultivars such as ‘Siskiyou’, there is a potential for early-season high-quality blackberry production in this region.

Technical Abstract: Little commercial blackberry production exists in areas with severe winters (minimum winter temperatures below ­18 degrees C and short growing seasons. In this study, we evaluated the combination of simple cultural practices, a modified rotatable cross-arm (RCA) trellis system, and covering plants with insulation material in winter to overcome the lack of cold hardiness in trailing ‘Siskiyou’ and ‘Boysenberry’ blackberries that have been established at Kearneysville, WV (39 degrees Latitude N). RCA trellis assembly has an upright post and a long cross-arm with a mechanism at the top of the post that permits the cross-arm to be pivoted and rotated as much as 220 degrees. A unique cane training practice spatially separates primocanes and floricanes. After tying canes to trellis wires and rotating the cross-arms to below horizontal, tied canes are close to the ground, allowing them to be covered with protective materials such as floating row cover (FRC) and polyethylene plastic (PE) during the winter months. Covers are removed in the early spring and canes remain in the horizontal orientation until bloom, encouraging flowering laterals grow upright. After bloom, the cross-arm is rotated to slightly beyond vertical. This positions the fruit on one side of the row and improves harvest efficiency. In January and February 2005, the daily minimum temperatures under the FRC+PE cover treatment were about 3 degrees C higher than in the open. The FRC+PE cover also provided protection against the wind. Tissue damage in trailing blackberries protected with a FRC+PE cover was significantly less than for unprotected plants. ‘Siskiyou’ plants in FRC+PE covered plots produced 3 to 5 times more fruit than plants in the open. Harvesting of ‘Siskiyou’ fruit occurred during the red raspberry harvest season or two to three weeks earlier than that for ‘Chester Thornless’ eastern thornless blackberry. Our findings suggest that trailing blackberries that lack winter hardiness may grow satisfactorily and produce fruit by mitigating the adverse effect of low temperatures and winds with our unique trellis system and winter protection system. RCA trellis system is amenable to cane manipulation and placement of winter protection material. The trailing blackberries could be included for fruit production in the eastern United States if practical cultural techniques for improving their winter survival become available. With addition of cultivars such as ‘Siskiyou’, there is a potential for early-season high-quality blackberry production in this region.