Wouldn't hurt to trim them. I wouldn't trim the main primocanes that will fruit next year. Mine are almost 6 feet tall now. The escapees (small primocanes) can be cut out now and wont affect production next year. you can also trim out the weaker canes if they are too close together. Had to do that with my Annes and Heritage last week.

I've planted Caroline and Ukee raspberries this year as well as, Ouachita blackberries. I thought I was supposed to top them off after they grew to three feet tall. True or not? I haven't done it yet, they are going on five feet tall. Mrs. G

Erect blackberries you trim at 42-48 inches so the laterals will grow. When you trim the plant it releases a hormone that triggers greater lateral growth which provides more surface area for blackberry production. Raspberries are different. They don't need to be trimmed to produce aggressively. They produce the laterals without trimming. Especially if you have an everbearing variety. If you do have an everbearing variety you trim the tops off after they finish fruiting.

Thanks ABz excellent advice. Mrs. G