Sure, you can prune them now. Congrats on the blacks growing so well!

Thanks! I'm so happy that they are doing well. How much do you think I should prune them? Just enough to get them off the ground?

If they are already back on the ground, I would prune them to the final length you would like them for over-winter, and then just prune off any new growth that occurs between now and the end of the growing season, as needed.

So larry_gene, sounds like you may be the one to direct this question toward so here goes:

I have not had black raspberries prior to now, I have reds which I cut down to the ground every year.

This year my sister-in-law asked me to come in and remove some of her black raspberries as they were going nuts. So I went in and sunk my spade in the ground and popped up about 20 different clumps of canes, brought them home and transplanted them.

It was not the optimal time for transplanting (this was on June 3rd) so I assumed I'd have a few not make it. Well, eventually 4 or 5 did die out completely, but the remaining 15 or so are healthy, and have quite a bit of new growth by now.

Thing is, I was hesitant to cut anything thinking these are the canes that will bear fruit next year, but they're starting to lay on the ground, and I assumed I'd get some tip rooting and end up with a bigger patch in the end.

But....., (And I'm showing my ignorance here I know) when you say to cut the canes to the height you want them to over-winter, does that mean if I snip the canes off to say 10" that they will still bear fruit on the new growth from that cane, or will I have messed up if I break out the shears now?

These canes didn't produce this year, so I assumed they would next, but I don't want to jeopardize a possible next year crop by cutting when I shouldn't be.

Can you advise me? If you were in my place, and had transplants that had not fruited, but are going strong heading into fall/winter, what kind of pruning would you do just now?

Thanks!

Thanks for the help larry_gene!

iowajer, no Larry meant cut the to about 5-7 feet tall. They should be on a trellis. Of no trellis, well they will probably tip root. Do not cut them down though. Yes at a 10 inches they would still bear fruit, maybe 5 or 6 berries. So no you don't want to do that!

Missy on laterals usually in winter they are cut to 18 to 24 inches. But no hard rule. If say the lateral aligns with a trellis wire, you could leave them as long as you want.
Best time to trim is late winter before spring growth. You can see the canes better, and shape them how you want. they should grow some the next year, but will mostly bear fruit. Actually they could grow a lot. I'm not sure? I only just purchased a black myself. My reds grow a lot both years!

If the new canes which we call primocanes are closer than 6 inches it's OK to thin them to 6 inches apart. Unless you only have a few. Then I would leave them.

Although there are different ways to prune black raspberries, I'm trying the advice listed in the Raspberry and Blackberry production guide for the northeast, midwest and eastern canada, NRAES-35, for my first year this year (see link):

For primocanes, prune when they're 28'' high back to 24''. This will cause them to grow many laterals

Tie laterals to trellis before it snows, Sept/Oct

In spring before bud break, prune laterals back somewhat if overly long (between 10'' and 24'' is probably fine)

Here is a link that might be useful: NRAES Book

This post was edited by JStubbs on Mon, Aug 19, 13 at 8:52

Good advice Jstubbs. Yeah 5-7 feet is a little tall. I was thinking more of blackberries. Although 28 inches is a little short IMHO. I would go to 48". But either way you should get a good harvest!
One reason it doesn't matter how tall, is I trimmed mine at 48 inches back to 36 inches, but currently the canes are over 50 inches with many laterals. The topping is to encourage laterals. Really height isn't as important as to when. I would trim them before August to give a chance for primocane laterals to grow. No matter what height they are.

Thanks for the info Drew51 and Jstubbs. When I went in to my sister-in-laws to dig these up, hers were all just in a big patch and I was thinking maybe they just didn't require trellising. She was getting loads of berries and they all seemed rather upright back in June.

But in retrospect, I imagine the only reason is that all the free space on the ground had been taken up. In my case, I planted them in a semi-circle behind a retaining wall of a circle drive and spaced them out accordingly. With that spacing they have plenty of room to sprawl out.....

So, this is good info - I'll put up some trellis system similar to what my reds have and I should be good, once I get the heading/pinching and all that jazz down!

Thanks again!

A trellis is nice as when they become loaded with berries, they will be on the ground, and can be stepped on, and all the ground insects will have a ball!
Speaking of no trellis berries I have some erect blackberries. Navaho is the cultivar. This one and Apache are nice cultivars that don't need a trellis really (I use one anyway). Also they produce top rate berries. Nice to have!