Answer: All blackberry plants are perennial, with roots living for many years. The canes are biennial; they grow one year (primocanes) and produce fruit the following year (floricanes). The floricanes die after they have fruited. New canes are produced each year from roots or the base of old canes. The floricanes need to be removed each year after harvest, but the new primocanes, which will fruit the following year, need to be thinned and trained. Perhaps you are confusing the growth of the canes? Poor fruiting can be due to insufficient sunshine or flowering during cold, wet weather. As long as your plants are healthy and producing new wood, they should bear prolifically - providing they have all day sunshine. Wish I could offer more information!
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