Anything you cut off will reduce next years production. To maximize production tie them up so that the canes are spread out as much as possible. You can do this so that they look neat and are easy to pick. Or tie them up in a more compact manner with a little less production.

Any kind of blackberry is going to be a mess unless you keep them under control. At least that's my experience.

Cut off all first-year canes. Keep all 2nd year canes where they are at least pencil-thick or larger, otherwise trim off wimpy cane ends.

How many second-year canes do you have?
Do you have any trellis at all?

Thanks for the responses. I'm not sure how many are second year canes, how do you tell the difference? I will take some pics and put them on here later today.

Dale

There is a trellis along the fence but I have chosen to run another perpendicular to it so that the bosenberries do not interfere with the blueberry bushes or the blackberries. I spent some time trying to untangle the canes and had to stop out of frustration. There are three nice size canes coming out of the ground and the rest are shooting out from those three. As you can see there is quite a tangled mess. On the trellis i am going to run 3 wires equally spaced apart, is it ok to just leave them tangled and put one large cane on each wire with all of the off shoots just tangled around them. Help please.

{{gwi:124947}}

{{gwi:124948}}

{{gwi:124949}}

You don't know what a caneberry mess is--yours is merely a small unruly clump, an indication of what can happen if you let them go. I pruned and threw away 4 times the mass of your patch and still have 4 times the mass to make berries next year. Of course your boysenberry thorns make the task harder.

Your idea to put the trellis perpendicular to the fence is good (never plant caneberries next to a solid fence). I would still prune out the wimpy little shoots in your pictures. Coax as much of the rest as you can onto the wires.

You would tell the 1 and 2-year old canes apart by which ones had spent blooms or berry cluster leftovers on them--those are the 2-year old canes.

My advice above (Oct 31) was misleading. By first-year canes, I meant the canes that grew in the first year and now are two years old.

I would just let it all go for now, don't try to sort it out, just tie them up to the wires. For the long term, I would let some of next year's canes tip-root in the middle or end of the trellis (farthest from the fence) and start new cane clumps there and eventually remove the fence plantings.

Somehow mark your canes that sprout up next year and after harvesting berries, prune everything but those new canes down to the ground.

Thanks Larry, then my blackberries should be trellised the same way?

What is your suggestion on the length of the trellises and how many wires?

Lastly for now, if the blackberry plants should also be taken away from the fence can I dig them up now since they have only been planted a few months ago or should i wait until spring?

Dale

Yes, you can trellis and prune blackberry varieties other than boysenberries in the same way. The newer primocane-fruiting varieties would be an exception.

Cannot advise on trellis length until I know how big of a berry crop you want in the future. The 3-wire system is fine; waist, chest, and head high.

I was under the impression the planting had been in for over a year. It's getting a bit late in zone 6 to be transplanting things, but blackberries are very forgiving and if you can get enough of a dirtball and drag it to the trellis area, next year's growth should not be greatly affected. Perhaps the soil would hold together better next spring for such an operation. In any case the plants should be moved before new canes start to emerge, as this also indicates delicate new root growth underground.

There is quite a bit of misinformation on the web about trimming boysenberries in late fall or early winter in much the same season that other cultivars are pruned. In some regions, however, boysenberries will appear earlier in the season than other cultivars — producing, for example, in late Spring or early Summer in Southern California where the berry originated — and so pruning a boysenberry bush some 6-8 months after it has produced fruit only impairs the ability of the plant to yield another crop. As to the bushes growing in a clump or "mess", it is often assumed that boysenberries can support themselves as they grow, much like their thornier counterparts. In reality, however, boysenberry bushes grow best when supported by a trellis or fence, otherwise the plant will spread out laterally making it more difficult to harvest the berries and more likely to succumb to pests.

Source: Knott's Berry Farm

Q. Should I trim at a particular time or let my plant grow forever?

A. You should trim right after your plant produces fruit.

https://www.knotts.com/blog-article/haunt/Knotts-Boysenberry-Plants

I think that comment is way off. the primocanes grow well if you remove the floricanes or not. The things are massive. i don't see how it could grow more if pruned right after fruiting. You can do this, it's not a bad way to do it, but if left on it makes no difference. At least with mine. I have done it both ways and have seen absolutely no difference.