Yes. I would tie them up. I did nothing fancy for my trellis. I just stuck bamboo poles in the ground about 6' apart on opposite angles and tied twine to it than loosely ties the stems the the twine. I can try to take a picture tomorrow so you can see what I did. ( picture is worth a 1000 words) I also just started spreading the wood chips from the bedding in my chicken coop on the soil of my raspberry's instead of in the compost. this has helped hold the moisture a lot and kept them from drying out. since I started doing this they have seemed to yield more, and I found putting the bedding in my compost was too much wood any way.