About seven years ago I started a patch of Triple Crown in my garden. I’m in Zone 5A. I’ve only gotten berries one year.
The primocanes are always vigorous. The floricanes never amount to much. Most don’t leaf out, and the ones that do wither and die shortly afterward. I’ve tried laying them down and covering them with hay for winter protection. I’ve moved the bed to a spot with less shade. We’ve had cold winters and mild winters. Nothing seems to make a difference.
Anything else I should try before I rip them out? And if I do, what should I replace them with?
You could try Wilt Stop, as dissication is the problem with these. But having to buy it every year is expensive. I would still cover too. You could buy a more hardier blackberry, like Darrow, Nelson or Illini Hardy Blackberry. All are hard to find. All thorny too. Chester is slightly more hardier and thornless.
But may fail too. Chester is not as good as TC but you’re not getting any.
I usually just leave the canes alone for the winter. Should I be pruning them back? Thinning them? Anything I should be doing with them in the spring???
Triple crown are hardy down to -10F. There can be other things at work if your climate has been warmer than that such as cane blight http://extension.uga.edu/publications/detail.html?number=C894. If the temperature has been colder than -10 F than consider a high tunnel installation rather than replanting because you have to much time invested in a crop and the roots are worth years of your time you can’t easily get back. Burying the canes in soil would likely work to keep the plants alive but that’s a lot of work. Do a test this year and try to build a structure over a small portion of the patch and see what you have next spring. How tall are they?
Yes, even if healthy. The plant can only produce so much sugar and nutrients. Topping them at 5 feet or 4 or 6 whatever, Keeping laterals no longer than a few feet to only 1 foot. Also only allowing so many primocanes. 5 or 6 at most, space them, remove small ones, or weak leaning ones. . Doing this will produce larger fruit with more sugar.
I agree with Clark, the high tunnel is a good idea. Protection from wind will solve your problem if it is above -10. Which is not really true, mine survived -16 and produced, but they were protected with Wilt Stop and leaves. The high tunnel should keep them warmer too, i would think?
I’m removing most of my blackberries. I’m producing way more than I need, so keeping the best of the best Triple Crown got cut. Excellent berry but is a crazy wild grower, too many suckers, hard to maintain. I prefer the less vigorous types. Which produce berries as good or better. SWD is a problem here too and TC ripens at the height of presence. So keeping earlier fruiting types, Tayberry, boysenberry, and New Berry, all of which I prefer over TC anyway. Keeping Marion too, and maybe Navaho, maybe not? I have not decided.
Good luck and keep us updated please.
I had a similar problem with both triple crown and natchez. Each year the majority of the floricanes would leaf out poorly and the fruit just looked bad if it had any at all. The pattern I noticed was that most of the bad producers had cane borer damage that started the previous year. You might want to check for enlarged areas of the cane. This is not a solution but one of many possible identifications for your problem.