Late fall and winter is the best time to transplant berry bushes. Blackberries and raspberries grow in a similar way with horizontal rhizomes that spread. When your berry bushes grow farther than you want them to, you can dig up the rhizomes and transplant them to a new area.
Dig up as much of the root as you can. Eight to twelve inches for each cane (stem) is ideal. If you’re not transplanting them right away keep the roots in a pot or bucket with several inches of moist soil.
Dig a hole the size of the root and about six inches deep. Put some loose soil in the bottom of the hole, lay the root horizontally about four inches deep in the hole, and fill over the root with more loose soil. You can add some finished compost to the soil, but not too much to avoid root rot.
Water every few days for the first few weeks and then just once per week. They are very drought tolerant so they don’t need much water. Occasional watering will help produce more canes and fruit in the spring.
Links to More Information
How to Transplant Blackberry Bushes https://www.newlifeonahomestead.com/how-to-transplant-blackberry-bushes/
How to Plant, Grow, and Harvest Blackberries and Raspberries https://www.gardentech.com/blog/gardening-and-healthy-living/how-to-grow-blackberries-and-raspberries
