How to Prune Blackberries

Have you ever noticed that berries taste best when picked at perfect ripeness from the plant? Too many times, I’ve been disppappointed by berries I’ve purchased from the store that are still firm and have been picked to survive transportation. Furthermore, I’ve been impressed by the selection of container-friendly berries that are available to home gardeners today (in case you’re concerned about space). Today you’ll be introduced to my container blackberry, as I share my pruning and feeding process. 

Here in Southern California, I grow blackberries in a container. My reasoning there is solely because I grew up picking blackberries on various trails in California where they grow like crazy. According to UCANR, there are both non-native, native, and naturalized types of berries here in California. I’ve seen firsthand how bushes can cover hillsides and become impressively thorny brambles—cool, but not what I was looking for in my small backyard. So, my sweet little ‘baby cakes’ blackberry resides in a half wine barrel planter where it seems to happy.

Blackberry Varieties

Unfortunately, I can’t give much guidance on which blackberries to grow, as I’ve only ever grown one—‘baby cakes.’ The ‘baby cakes’ blackberries are a dwarf thornless variety that are supposedly perfect for containers. Mine was a clearance plant, so the price alone was enough for me to bring it home! After more than five years (not really sure on that timeline) I can say that ‘baby cakes’ has stayed thornless, but not dwarf exactly. Case in point, my blackberry’s canes are supported on a wooden trellis and sometimes measure as long as four or five feet long!

Another thornless blackberry variety I have heard good things about is ‘triple crown.’ I think if I added another variety to my garden, it would be that one.  

In the end, I’m happy with the blackberries ‘baby cakes’ has produced while being nicely contained in a pot. About once  a year, right after I prune my blackberry plant, I also top with compost and fertilize with a berry-specific fertilizer. Additionally, if my pot is looking low in regards to soil level, I’ll top it off with an acid-mix potting mix as well.

When to Prune Blackberries in Southern California

 As far as I know, pruning blackberries is generally the same no matter what variety you are growing. In fact, it’s extremely similar to how to prune boysenberries too! The ideal window for pruning these types of berries is between December-February, but lets be honest, there’s wiggle room. Sometimes I stress myself out trying to finish all the pruning in the dormant months, so I just try and do a little at a time!

Below I’m going to cover how I go about pruning blackberries in written steps, but you can also join me in the garden and watch my YouTube video too!

How to Prune Blackberries~ Start with the Old

The first thing I do before pruning blackberries is to look for canes with old blossom parts. These are the canes that fruited last year, which means they won’t fruit again. Follow each of those canes allllll the way down to the base of the blackberry and cut it off.

While you’re removing old canes from your blackberry plants, keep an eye out for dead/diseased/damaged canes too. Anything that fits those criteria needs to be removed to give the plant a healthy start!

Support the Remaining Canes

After removing the old, previously fruited canes and anything dead/diseased/damaged you’ll be left with canes that will be fruiting this coming year. These leftover canes are the canes we want to support if necessary. Before supporting the canes, I’ll usually decide if I want to keep them all. For instance, Sam and I have multiple boysenberry plants, so we typically only keep 3-4 main canes on those plants to keep them organized and let the plant focus on producing the most fruit there. On the other hand, I only have this one blackberry, so I tend to let it be more “wild” and keep whatever canes it produced that year. Sorry that’s not really scientific or anything. The only exception would be thorny canes. If I see thorny cane on a “thornless” plant, I remove them so they don’t try and take over.

Once I know what blackberry canes will be growing and fruiting this year, I attach them to my trellis. Essentially, I make sure each cane has some support if they are long. You can use twine, elastic (I had old velcro bands), or really anything you’d like to secure your blackberry canes to the support structure. Please note: don’t tie them tightly enough to suffocate the cane!

Feeding & Topping Off Blackberry Plants

Once you are finished pruning your blackberries, it’s time to prepare the plants for a bountiful season. Per usual, I like to add compost around the base of my blackberry plants. Mix some organic berry fertilizer at the base too! Most berries like a slightly acidic soil, so I’ll top off any potted or container berries with some acid-lovers potting soil to finish off the process.

Water and mulch!

This time around I did not water my berry because we were anticipating rain (and we got TONS)! Typically, I’ll water my berry and mulch around the base to keep everything nice and cozy.

If this post felt short, that’s because it was! Haha. Caring for and pruning blackberries is one of the quickest tasks in my garden right now compared to the other impending pruning tasks (ahem, stone fruit and roses I’m looking at you)! If you’re looking to add more berries and fruit to your yard, this is the perfect season to shop for bare root berries and bare root fruit trees. Make sure to check out Things to Consider Before Buying a Fruit Tree for some help selecting an appropriate tree for your climate, and follow my No-Stress Bare Root Planting Guide. Happy growing my friends!