For anyone who grows blackberries, grapes, black raspberries, there is a device that is a REAL time-saver! It is called an HTB2 Tapener.
Back when I grew tomatoes for sale, it took me ten afternoons to tie them all to their stakes. After I bought a tapener, the task took three hours. A HTB2 Tapener is a hand-held tying machine allowing vines, etc. to be tied to their trellis in 2 - 3 seconds. It saves me so much time that I share its use with everyone I know. I bought mine from a company in Minneapolis, MN, called MDT & Associates. Their email is mdtgrow@juno.com .