Answer: Those canes coming from the ground next to the plant are root suckers, which are produced every year. Some of these should be cut to the ground every year, so that the row is no wider than 1 foot across and each clump contains about 6-10 canes. The best time to do this is in early spring. Don't remove the thickest and healthiest ones. After you've cut these new canes that are growing beyond bounds, cut out any canes that have fruited (those with old, cracking bark) or ones that are damaged or dead.
Upright blackberries bear fruit on branches that grow from these upright canes. You can encourage more branching by pinching out the growing tips of new canes when they are about 3 feet tall. Do this several times during the summer. Then during the winter, prune these canes again, shortening them back to 4-18 inches.
It sounds like a complicated process, and it does require management because these plants would like to grow like weeds and take over. Of course, we benefit from their vigorousness when we direct their energy toward producing fruit for us!
Q&A Library Searching Tips