Double Tipping Darrow Blackberry?
I planted a few Darrow Blackberries a 4 years back, barely produced any berries, except 2 years back - but they were small and crumbly. So, last winter I cut them entirely down to the ground and this year I have been soft-tipping at 39 inches. My question is, what is meant by double-tipping? Do I tip the laterals also and at what length?