|the bush is from last season and I want to cut it back not sure how far the branches are long|
|Pruning raspberries is fairly straight forward: With garden shears, cut back all canes that have died during the winter to ground level in the early spring, and then cut back all remaining canes to about chest height. Cut to soil level all canes that have borne fruit that year. It's easy to tell: If you do your pruning soon after harvest, you'll see the remains of clusters where the berries have been removed. If you wait until fall, look for the darker canes with peeling bark. Remove any canes that look weak or diseased as soon as you see them, at any time of year.
Take out new canes as you need to so that there's about six inches between all canes. Pull up all suckers (new canes that sprout up from the roots) immediately. All raspberries will take over the neighborhood if you give them half a chance. Good luck with your raspberries!