Transplanting wild blackberries could also transplant diseases to the garden. Commercial blackberries---certified free of disease---offer improved size and yield over their wild cousins and are the best choice for home gardeners. A healthy patch of wild berries could rival the domestics for size and flavor when planted in a fertile location. Proper transplanting techniques give the plants the best chance for a new start. The same nurturing tricks that improve the yields of commercial blackberry varieties also work for plants from wild stock.
Select only healthy and productive wild blackberries for transplanting. Inspect the plants during the fruiting season to determine whether berries are of good size and quality. Check again toward the end of summer to look for curled or discolored leaves or lesions on canes. Don't dig plants from diseased thickets even if individuals seem healthy.
Dig blackberry plants in the late fall when leaves have fallen and the bushes are dormant. Clear out dead canes before digging to avoid thorns, and cut the living canes of transplants back to 12 inches in height.
Use the mattock or hoe to dig a trench around the selected plants. Dig about 6 inches deep and at least 6 inches away from the main canes. Trim feeder roots by clipping with pruning shears. Blackberries root shallowly and sprout new canes from horizontal runners---so include as much of the root system as possible.
Set the blade of the transplanting shovel under the plant and lever the blackberry out of the old site, taking old dirt along with it. Bag both plant and dirt to prevent the roots from drying out.
Collect sections of horizontal feeder roots as well as the upright canes. Blackberry root cuttings 4 to 6 inches long and over 3/8 inch in diameter can be trimmed at both ends and replanted. Most will send up canes the next year.
Soak the plants in a bucket of water for a few hours before planting in new ground. Rinse the old dirt carefully from the roots and plant the blackberries 2 feet apart at the same level as they naturally grew. Water the ground thoroughly and mulch the new bed 3 inches deep with leaves or straw for the winter.