It's awfully easy to let even thornless blackberries turn into an impenetrable jungle.  Just forget to tip prune them one summer, then you're unable to mow the tall weeds that pop up under their arching canes.  By fall, the row looks like a wild briar patch.

The first step in renovating a patch like this (or any other kind of overgrown bramble) is to prune out the worst canes.  I snip off all of the rooted canes in the aisle and then cut the plants back to a main stem with branches six to twelve inches long.  Meanwhile, I pull or cut out dead canes from previous years.  I'm not really pruning yet, just opening up the patch so I can get in there.

Next, I dig out any tall weeds that rooted within the row.  Ragweed isn't a perennial, but once plants like wingstem get a foothold in your bed, even a kill mulch will have a hard time holding them back.  I might accidentally dig up a berry or two in the process, but that's not a problem --- there are plenty of brambles left.

Now that I can see what I'm doing, it's pretty simple to prune the blackberries using techniques I've explained previously.  After a good pruning and weeding job, I lay down a kill mulch along side of the berries to prevent the bad weeds I might have missed from encroaching into the planted zone.  Then I top it all off with mulch and mark a remulching and summer pruning job on my June calendar to ensure the problem doesn't reoccur.

Luckily, brambles are awfully forgiving of even the worst care.  Even though this patch looked like a jungle last summer, it will probably produce pretty well for me this year (and even better next year if I manage to keep the weeds down).  Our blueberries are more daunted by weeds, and I can see a big difference between the plants I managed to remulch last summer and the ones that got away from me.  Maybe next spring, I'll be so on top of the perennials, everyone will be in good shape.