If you want to maintain them as twice fruiting plants you'll need to to do regular maintenance pruning. If you didn't do it last fall, you can still prune out any dead canes. Canes that bore fruit last summer will not do so again. Then thin canes so that you have 6-8 per foot of row. If you just want them to produce a fall crop you can simply mow them off in late winter or early spring. If they're starting to leaf out you probably don't want to do that anymore this year. For more info you can go to www.extension.umn.edu/gardeninfo This is a great website with lots of info.

Here is a link that might be useful: MN extension website