Hi,
Raspberry canes definitely need support. A common practice is to build a very sturdy T with 2 cross bars for each end of your row. The T can be metal or wood, it doesn't matter. The lower cross bar should be about 30 in. off the ground, and the upper one about 50-60 in. Then put eye bolts, or something similar on the cross bars, one near each end, and string heavy wire between them. This makes something like a giant rectangular cage. The wires on the bottom catch the short canes, and the wires up above hold the tall canes. The raspberries will get heavy and multiply over the years, so you want the posts to be very well "planted" and the wires to be very tight because they will begin to droop over time and become pretty useless. You don't want to be forced to do this twice! There's a technique for securing the wire so it can be tightened, but I don't know what it is.
I wasn't allowed to post a pic here, but if you click "view my page" on the left you'll see it. The raspberries are on the left edge of the pic. You don't see the eye bolts because they are screwed into the inner side of the 2x4s.
