over run by Blackberries

Okay, so a few years ago it seemed like a good idea to plant a few blackberry bushes(thornless yeah baby!).  Thanks to the great weather this year in this part of the country, I have been over run by the darn things!!!  How many jars of blackberry jam (seedless mind you) and blackberry syrup and blackberry vinegar and blackberry cordial.....need I go on???  Needless to say the bushes are getting quite a hair cut for back to school let me tell you!!!