All of this is certainly true. May I offer an additional thought: my greatest success at controlling non-native blackberry is to get the whole plant out by the root. From now through the end of rainy season, I work to get to the base of a plant and pull it out. Usually, a decent pair of leather gloves is all I need because the plant's thorns get smaller and more fragile at the base. If I cannot pull out the whole plant, my favorite tool to get the root out is a pulaski. Unless you have goats to keep the plants chewed down, getting the plant out by the roots is the only way to get ahead in the blackberry wars IMHO.