If you know you're gonna get a bit cold, throw some hay or a tarp over them to keep them warm. Don't uncover them until the chance of frost is basically over.

Are the canes on the trellis during the winter or on the ground? I just planted Triple Crown and I have been trying to figure out how to set up the trellis. From what I've seen, I think I should leave the primocanes on the ground, mulch them over the winter and tie them to the trellis in spring.

Here is a link that might be useful: Tales of a Transplanted Gardener

My canes are trained on the trellis. I have tried to tip them at 42-48" to force the laterals to grow. Some canes, I leave long to let the tips grow roots for more plants. I have also read that training them to the ground and covering them to insulate them for the winter is an alternative. Those canes get thick and to get them to lay on the ground will be a challenge, let alone the amount of work (if you have a lot of them) and them to train and weave them back on the trellis in the spring. I may try a section and see if that can work? I also read that a "V" trellis may be the answer in that the floricanes are on one side and the primocanes on the other. This way they are separate and it would be easier to cover and insulate. Insulating them on the ground would be easier, plus the snow helps to insulate from the frigid weather

From your description, it sounds like the cold wather got the canes, unless you're looking at last years' floricanes (which die after fruiting), but it sounds like you know enough about blackberries to not make that mistake.

Triple Crown and Chester are actually semi-erect types, not trailing. Trailing types are bred here in the Pacific Northwest, and are mainly used for processing. Some popluar varieties are Obsidian, Black Diamond, and Marion. The canes of Triple Crown and Chester are too thick and grow too erect to keep them on the ground and cover them during the winter.

My Triple Crown gets a little dieback at around 0F, so it may be a little too cold for the trellised canes to winter through for you. To make them work, you may have to cover/insulate them as recommended above. I had heard Chester was a bit more winter hardy than Triple Crown, but apparently not much.

I believe we got down to about -3 this year here in RI. My unprotected, trellised Chester's did get any die-back.

Some of my Chester canes are almost 1" in diameter, so I don't see how I'd bend them over to the ground to protect them. Though, it might be fun to re-design my trellises to allow for a 90 degree hinge function! :-)
-Glenn

I think we got down to -18 for a couple of days. I think I may have to stick with the Illini Hardy. I am trying Prime Jan this year, so I hope that it turns out better than the Triple Crown and Chester. Now, a problem that I have is that I tip layered a bunch of them. I now have close to 60 Triple Crown and Chester plants