Lisa,

Blackberries produce most of their fruit on two-year-old wood. In other words, each nice strong green cane that grows needs to suffer some winter weather before it will produce most of its fruit its second year. Then after that, it dies or is close to death. I think this is why you are seeing some of your canes falling off. They have fruited over the past couple years and are now dead or not worth keeping. At the same time, you have a lot of brand new bright green canes coming up. Those will not produce much fruit this year and should be left alone to grow until they are about 4 or 5 feet high.

So basically, here's what you need to do:

Each winter (or I guess you could do this right now if some of your canes are falling off), identify the canes that look totally dead and full of branches and ready to fall off, and cut them off at the ground. These ones have already fruited and thus must be three years old and are no good to you anymore. If they have fresh flowers, you could keep them this year but I'd whack everything that wasn't vigorous and green next winter.

With the canes you have left, they should be greenish-brown instead of a dull gray. Thin the greenish ones out so that there is one every ~4 inches or something like that. It's not good to have them so close together that you cannot reach all the fruit. A lot of growers say that each plant that you originally put in the ground is reall only intended to grow maybe 5 or 6 canes at one time, so if your original plant is growing 10 or more canes, then you have way too many! Pick out the weakest ones and cut them off at the ground, and leave all the strong green ones alone.

Each summer, when the green ones get to be around shoulder height, cut the tops off to promote more fruiting branches for next year. If they don't get to be shoulder height, you can just leave them alone. You'll also want to tie them up so they don't fall over.

Each year you should have about a 50/50 mix of brand new green canes that don't produce fruit, and older brownish canes that produce all of your fruit and then die in the winter. So then when winter comes, you cut the dead ones off, and new green ones grow to take their place next spring while the green ones from last year make your fruit.

Make sense now?

Thanks for the info! I think I get the basics. Canes fruit in the second year, so prune new canes to make them branch and tie them so they don't break, cut out the wood that's already fruited, and leave what was "new" the year before to fruit in the current year. That right?

I have shoots coming up out of the ground at various spots around the main plants - I'll let them grow, prune the tops and stake them for next year. What I'm not sure about are the mass of branches I have now. Most of the canes I have now are "shoots" that grew out of the stumps of all the canes I cut back. If a new shoot came out of an "old" branch, will it fruit? Or should I prune out everything that comes from these older branches? Or are all my canes now first year canes? But that can't be because I do get fruit every year - guess I'm not as clear on things as I'm thinking!

I couldn't seem to figure out why I had so much growth that never produced any berries - I had no clue canes didn't fruit until the second year. I figured since I never pruned, a lot of branches probably weren't getting enough light so they weren't flowering and producing. Somewhere I heard to cut everything back to a couple feet in the spring and just let them go, so that's what I've been doing.

Lisa

Yes, you understood the basics as explained by Lisa.

If you have shoots coming out of the ground and they look fairly robust or thick, tend to those and remove all the shoots that are starting above ground from old pruned canes.
You could try pruning those old canes even closer to the ground.

You might keep a couple of the above-ground shoots just to compare how they fruit next year compared to the ground shoots.

Let any laterals get long until they get in your way and prune them at that point. If you eventually end up with too many berries, you can prune the next year's laterals shorter.

Hello Lisa,

Perhaps you would do better with a different variety. The Universicty of Arkansas came out with two new varieties a decade ago caled, "Prime-Jan' and 'Prime-Jim'. Please pause a moment and Google those two terms.

These are really different. First of all, they are fruit-bearing primocanes. Yes, that's right. First year fruit!

From what I have read, you get a summer and a late summer/early fall crop each year from every cane. This fall, I will be building a large organic bed, and in the winter, I will buy a mess of both varieties and put them in the new bed.

One problem you are having is that the canes snap off in the wind. Using a different variety, especially a lower, semi-erect or non-erect variety might be just the thing.