Ask Gardenerd: Pruning Blackberries

As we look into the corner of the Gardenerd Test Garden, we see the need for blackberry pruning. Someone else in the Gardenerd community did the same thing and asked: “I believe you mentioned it is time to prune blackberries, but what’s your method? My Seattle friends say they all cut the plants off at ground level and tear out the runners invading new territory. My plants are 2 years old. What is best pruning method for the maximum yield next year?”

Before we prune blackberries, let’s talk about how they grow:

Blackberry flowers

For the sake of simplicity, let’s say blackberries have floricanes: they fruit on second-year canes. This means that a cane (or stalk) will grow tall in the first year, but it will only set fruit in the second year and then it will die back. So if you want fruit every year, cut down only the canes that fruited this spring/summer.

Some people tie ribbons around the canes that fruited, but we just wait until those fruited canes die back and turn brown, usually in winter. Step One: Cut all the brown canes back to soil level and leave the green canes for next year. Leave 5-6 green canes for each plant.

Prune blackberry canes that have turned brown. Leave green canes in place.

Prune blackberry canes that have turned brown. Leave green canes in place.

Step Two: Tip-prune green canes back to 4 feet above ground. This will help generate bushy new growth when the time comes. You can also prune any lateral branches (side shoots from the main canes) back to 12″ inches.

First blackberries of the season

This cane will be cut back at the end of the season.

Step Three: Dig out those runners! Blackberries are vigorous runners. Those runners can travel across the yard. Our blackberry plant started as a cutting in a pot, it now pops up as far away as ten feet from the original plant.

It's time to dig up blackberry runners before they take over. This one grows between two potted plants.

It’s time to dig up blackberry runners before they take over. This one grows between two potted plants.

Dig runners out with a shovel and follow them back to the source as much as possible. Runners send up new canes all along its length so be vigilant. A little effort every couple of months will restrict blackberries only to designated areas.

Note – there are different types of blackberries and other cane berries. Some have canes that don’t die back at the end of the season, and some have both primocanes (that fruit in the first year) and floricanes. These instructions work for blackberries with floricanes but may not apply to raspberries or black raspberries that have a primocane-growth behavior. If your plant doesn’t exhibit the growth behavior mentioned above, read up on the variety you’re growing to be sure you are pruning the way it wants to be pruned.

Sharing with friendsTweet about this on TwitterShare on Google+Pin on PinterestShare on FacebookEmail this to someone
This entry was posted in Blog, Sage Advice and tagged , . Bookmark the permalink.

4 Responses to Ask Gardenerd: Pruning Blackberries

  1. Michael Doty says:

    Those super fast growing long shoots i have coming up this year, are these my new growth that is going to fruit next year? Or are these suckers that i need to cut out? Just a little confused because i have new growth in the form of stems that are like a foot or 2 now, but the ones i am asking about have shot up and are over 8 feet long now. Thank you

    • Christy says:

      Technically those should be your first year’s growth that will fruit next year. If they are in your way you can tip prune them back to 4 feet long and they will branch out next season. If any of this new growth is sprouting from an area that you consider “out of bounds” just dig them out or they will take over your yard.

  2. Sue says:

    I have some of the above blackberry and they have gotten way to big because we didn’t know how to take care of them. My question is can I prune them back now. I live in lincoln county wv.

    • Christy says:

      Hi Sue,

      Winter is the best time to prune back blackberries. You can even prune them if they are starting to bud already. I did that last year, and my yield was lower but I still got a decent harvest. Dig out runners that have crept out of bounds, too. Don’t just snip them back to soil level. Take the time to really dig them out and you’ll be much happier when it comes to harvest time.

Leave a Reply

Your email address will not be published. Required fields are marked *