Once you have picked all the crop from summer-fruiting raspberries, loganberries and tayberries, you should prune out the old stems. Annual pruning keeps the plants vigorous and productive, so you get the best return from your plants for the space.
Work your way along the row, cutting out all the fruited stems right down at the base. It should be easy to spot these old stems, as they will be brown in colour and still carry the remains of the fruit stalks. Take care not to damage the bright green new stems.
Next, go back along the row and thin out any of the new stems that are overcrowded or weak, and remove any growing too far away from the row. Ideally the new stems should now be spaced about 20cm apart. Finally, tie them in to horizontal wire supports.