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

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.

This Post Has 12 Comments

  1. Denise

    Please talk more about the runners, how many to expect and how to dig them up. And if there are some varieties that do not have runners and general guidelines for where to plant them as I’m surprised your potted blackberry still produced runners in the ground! I currently have a runner problem with a row of 4 blackberry plants, which sent runners into my neighbors yard where they are not wanted. to stop the problem I pulled up my 4 blackberry plants and put them into 4 large pots. But you say they will not stay contained in the pots and still produce runners in the ground?

    1. Christy

      Our blackberries ran because they grew through the drainage hole on the bottom of the pot. If your pots have saucers underneath or on a solid surface, they will stay contained. As for how many runners – an endless supply. We pull runners every week or so and unless we go out and dig out the mother roots underground, they will continue to send up shoots for all eternity. While it’s possible that some hybrid varieties may not have a spreading habit, I don’t know of one off hand.

  2. Teresa Emerson

    I just bought 2 apache “top rooted” I know have to wait 2 years for my first crop as this variety only bears fruit from floricanes. My question is two fold. First. 1) about how many new canes on average (including suckers) can i expect from this variety of blackberries and 2) usually when “tip rooting” is done does that speed up the process for getting my first crop? In other words. Since you use primocanes to do your tip rooting is the DNA already in the tip to tell the canes next year to produce?

    1. Christy

      HI Teresa, I wish I could accurately answer these questions, but the answer – as with most gardening questions – is it depends. Apache is supposed to have an “extra-fertile flower” so producers say it gets higher yields. As for canes, I can only speak from my own experience. Most years I’ll see 5-7 new canes growing that will produce the next year. As for tip rooting, since the plant is spending energy on forming new roots and growth on that buried tip, that means there is less energy for making fruit. So I would choose a cane that isn’t fruiting, strip the leaves from most of the cane, then bury it to initiate rooting. The new shoot will still be siphoning nutrients and energy from the mother plant until you cut the cord. Once you do that it will be its own plant and the mother plant can go back to focusing on fruit production.

  3. Larry

    I just bought 3 potted blackberry bushes they are prime ark they are about 2 feet tall how and when should I trim them and are they gonna make berries next year one has a couple berries on it thank you

    1. Christy

      Hi Larry, took me a minute there to figure out what you were saying since there’s no punctuation in your question. But I figured out that Prime Ark was not a typo – it’s is a cultivar of blackberry (the first thornless variety developed out of Arkansas, so that makes total sense). That particular cultivar is a primo-cane variety, meaning it produces on first year canes and you don’t cut those down to the ground after the fruit (as you would with 2nd-year cane type varieties). Here are the instructions from Burpee on pruning primo-cane varieties:

      NOTE: For Primocane Bearing Blackberries: These bear fruit twice on the same cane. Prune new shoots each year as for standard blackberries. New shoots bear fruit at the tips in fall, and further down on the cane the following spring. Cut back old canes after the second crop is harvested.

      Depending on where you live (whether you get a frost or snow or are frost-free) you’ll want to prune the canes after they fruit, and usually after they discolor a little. Probably late fall. You may want to tie a ribbon around those pruned canes so that next year you’ll know to cut them all the way down to the soil after they produce fruit.

      I hope this helps.

  4. Michael Doty

    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

    1. Christy

      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.

  5. Sue

    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.

    1. Christy

      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.

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