You make wine from blackberry cuttings just like you can from grapevine cuttings.
This wine is really quite good, so we aren't making it on faith anymore. You can make it throughout the spring and summer seasons or whenever you get a renewed spurt of growth after the berries fall (or are picked). Arm yourself with rawhide gloves, prunning scissors, high boots, and at least a gallon-sized bucket and head for your favorite blackberry (bramble) patch. Cut yourself a gallon of loosely packed tender ends of blackberry shoots and head for home to start this wine.
Boil the blackberry tips for one hour, adding water to replace evaporation. Put sugar in primary and strain water onto sugar, stirring until dissolved. Cover and set aside to cool. Stir in acid blend and nutrient, then add activated yeast. Recover and put in warm spot. When active ferment dies down (about 7 days), transfer to secondary and fit airlock. Put in warm place until fermentation completely stops. Rack into santitized secondary, top up and refit airlock. Move to a cold place for six months, checking airlock occasionally. Rack into bottles and age additional six months. [Adapted from recipe by Women's Institute Members' Home Made Wines, Syrups and Cordials, 1954, London]