My blackberry picking has been taken to the next level with the addition of another year of martial arts training and a tonfa:
I have used the staff in the past. It is good for peeling away the outer layers of fresh thorny vines with no berries, to get to the fruit-bearing vines. I will stick it in the ground at an angle, then use it as a lever to move all of the vines around in a big clump.
The tonfa is excellent for close-in work, allowing me to move and rearrange the thorny blackberry vines in order to more easily grab the berries. In the past, I was doing this by hand, but the tonfa allows me to easily, quickly, and safely manipulate things. As a result, I was able to gather the blackberries more quickly than in the past, and with fewer scrapes.
The tonfa was originally an agricultural tool, a handle for grinding stones. Nowadays it is seen exclusively as a weapon, but I have taken it full circle by using it as a tool to collect food. I like the symmetry of this.
I will also mention that martial arts kicks are very useful for clearing out and stomping the vines, especially crescent and reverse crescent kicks. When roaming through fields full of blackberries, you have to be willing to destroy and flatten some of them. If you do not cut paths, the berry vines merge into a giant impenetrable tangle of thorns. These briar patches do not even produce many berries, because the sunlight never gets to them. Selective culling with kicks and the staff are needed to keep the right density and ensure that there will be lots of berries each year.
The blue thing in my pants pocket is a nifty mosquito-repelling machine that my mom had and asked me to try. It works well.