Gmshack - I have read of using both plastic and Agribon, but haven't gotten around to the plastic part yet. There are two main issues with overwintering and some studies suggest that dehydration is a bigger problem than cold tolerance in cold climates. I used drew 51's technique of Wilt Stop this fall, so we will see if it prevented desiccation. I also used two layers of Agribon. I find that one layer does not provide the protection that the company claims. I start covering mine around late August when our first frost hit. This is both to protect berries and reduce temperature shock from early season frosts. In the spring, I am leaving the Agribon on for a few weeks. This next spring I will leave it on until each variety begins to flower. This substantially increases growth for me (in our very cool Mays) and hastens flowering by a few weeks. I do remove it on days with temps over 70F. Desiccation is a real problem for me since our ground is frozen solid for at least 6 months out of the year. Add to this that preliminary probing this last summer suggested that blackberry roots up here only extend 3 or 4 inches into the ground (it is too cold below that, with an average annual temperature at 3 ft of around 31F). In this situation I believe that the roots cannot take up water to replace what the canes transpire during the winter and they end up desiccating and dying way back (from 8-10 ft long to about 2 ft). We will see. As far as the weed block, it will probably not increase the soil temperature as much as removing it. I'm not sure of this as I don't have experience with it in the Lower 48. Up here, it must be removed in the spring for about 4 weeks to allow the soil to thaw and then reapplied. Your soil is already thawed and substantially warmer, so you shouldn't have to do this. What I think I get from weed block is increased heat above it = though I have no data to show that. I just know that of two Wild Treasure plants I have (that are one year different in age), the one grown over weed block is much more vigorous than the other. I trellised the very vigorous one last year and it continued to grow strong even though most of the canes were not directly lying on the weed block. A study at Oregon State Univ. also supports this. However, Wild Treasure is a crown-forming variety, not a spreading variety like the ones you have, so covering around it with weed block is a simple process. I do not grow primocane blackberries because the season is too short and there is insufficient heat. Everyone of them has died completely. I have one Triple Crown left and a very wimpy (it grew 2 whole inches this year) Chester. Neither has canes that survive - but then I have not covered them. I am guessing that if your TC canes survive and leaf out, but don't flower, that the flower buds are damaged by the cold. Flower buds on many plants are much less tolerant of cold than non-flowering buds. I have two varieties of erect blackberries that I am trialing that might be of interest to you. They are Nelson and Stenulson. Stenulson has been in the ground for several years, but moose have browsed it down each year and voles girdled anything that was left. Thus, I don't have an idea of its ripening season, but it is likely too late for me. It grows pretty well here and is spreading (unlike TC and Chester which only get smaller each year). I have had a few green canes survive the winter and start to leaf out and then die because they were girdled by voles at the base, so it is pretty hardy (though these were covered by snow mid-winter, when air temps dropped as low as -35F). I just got Nelson last year and it actually flowered earlier than any other erect I have. Its berries are somewhat frost tolerant, as well, to at least 28F. It still did not ripen early enough, but it was in a pot and not established. The timing could change in the future, especially if I put an Agribon "sack" over it early in the season. Both of these are thorny. I got Balsor's Hardy Black from the USDA germ plasm repository this fall, but it failed to root before it rotted. This is another possibility, but it is not commercially available in the US. Happy New Year!

Crown blackberries should be big at planting time just after fruits get into green stage new canes should a pier then again after fruiting ends. Zone 5 pushing limit of time for blackberry plant do its thing I hope you have all sun you funnel in to plants reflective heat would help as in warm place by tin wall on North side plants. If canes flowering now 13 June after 3 to 4 weeks from now July 14th there be change first year all ways slower.

Pruning is done at various times. Your raspberries are both fall bearing cultivars btw. Primocanes are 1st year canes Floricanes are 2nd year canes Fall bearing bear fruit on both primocanes and floricanes. Primocanes will have a fall crop on upper 1/3. The next summer lower 2/3 will fruit (now called floricanes). You can just take the first crop and cut them down. Or you can also take the summer crop. Up to you. If you want both crops once primocanes are done fruiting, cut off upper 1/3, and leave the bottom 2/3's to fruit next summer after winter. So a new cane will fruit in fall, then the next summer will bear fruit again. It is confusing! Some just take one crop to make it easy. I myself take both crops. Blackberries and summer bearing raspberries fruit on 2nd year canes only (floricanes). With blackberries you want to tip them at 4 feet. They will produce lateral shoots, and produce more berries. You can tip them when they reach 4 feet. This is not a set rule, 3 feet or 6 feet, is OK. If left to grow too long berries can break canes from the weight. So best to prune them. New canes come from the crown with blackberries. Just leave them. It doesn't matter how many. Raspberries throw suckers that come up all over. A rule of thumb is to space about 6 inches apart. Any closer it becomes too crowded, not enough light or air flow. Blocking air flow encourages fungal growth. So if new canes are very close, you can thin them out. Do this when dormant. Once floricanes fruit in done, remove them ASAP

What about redcurrants? These will do well in a pot culture and can also be grown as cordons - a very versatile and tasty currant. Blueberries are another possibility but it must be kept wet - really wet, and prefereably not with tap water either (complete lime haters, ph 4.5). I may try them again with a seep hose directly from one of my water butts but if watering is not a problem, they are also very good plants as well as being quite stunningly ornamental. Yep, there are smaller, more upright blackberries, as well as loads of hybrids between blackberries and raspberries but I think it would be almost impossible to grow raspberries or most blackberries in pots because the cane renewal requires several new canes being produced every season and they tend not to grow close enough to the original crown. Finally, vines can, and are, very successfully grown in pots - the trick is in the pruning - it is OK to grow them as a really tight standard with a minimal framework. Again, they are also good on any training system. They are vigorous so you have to be firm, but definately more doable than the berries. Oh yeah, blackcurrants are also brilliant in pots - especially the smaller (but very prolific varieties like Ben Sarek). I am mad for fruit and grow as much as I can at my allotment.