Pruning Raspberries and Blackberries: Keep Your Fruit Canes Productive

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Right, let’s talk about one of those jobs that a lot of people either get wrong, put off until it’s too late, or just skip entirely because it seems confusing. Pruning your raspberry and blackberry canes. I get it — standing in front of a tangled mess of thorny canes in November trying to work out which ones to cut and which ones to keep is about as appealing as doing your tax return. But get this right and you’ll be rewarded with loads of healthy, productive fruit next summer. Get it wrong and you’ll end up with a jungle of weak, unproductive canes and barely enough fruit to put on your morning cereal. Ask me how I know.

My first couple of years growing raspberries were, being kind, educational. I basically didn’t prune them at all because I was terrified of cutting the wrong thing. The result? A dense thicket of spindly canes that produced about twelve raspberries between them. Ronny came over, looked at my raspberry patch, and said “That’s not a raspberry bed, man, that’s a hedge.” He then spent twenty minutes showing me what to cut and what to keep, and the following summer my raspberry harvest tripled. Tripled! All from one afternoon’s pruning. That’s when I realised this stuff actually matters.

Understanding How Raspberries and Blackberries Grow — The Key to Everything

Before you pick up the secateurs, you need to understand how these plants work, because once you get this, the pruning logic makes complete sense. Both raspberries and blackberries are what’s called biennial croppers — well, most varieties are. They produce new canes (called primocanes) one year, and those canes fruit the following year (when they’re called floricanes). After fruiting, the cane dies. So at any given time, your plant has two generations of canes growing together: this year’s new growth and last year’s canes that are currently fruiting or have just finished fruiting.

The dead canes — the ones that fruited this year — are done. They’ll never produce fruit again. They’re just taking up space, light, and air circulation. Those are the ones you cut out. The new canes — the ones that grew this summer but didn’t fruit — those are your money-makers for next year. Those are the ones you keep, tie in, and look after.

Now, there’s an exception. Autumn-fruiting raspberries (like Autumn Bliss, Joan J, and Polka) work differently. These fruit on the current year’s growth — the primocanes. So the pruning is much simpler: you just cut everything down to the ground in February and let it all grow fresh. Easy peasy. More on this in a bit.

Pruning Summer-Fruiting Raspberries — Step by Step

The best time to do this is as soon as you’ve finished picking the last of the fruit, which for most summer-fruiting varieties is late August or September. But if you’ve put it off (no judgement — we’ve all been there), you can still do it any time from now through to early winter. Just don’t leave it until spring or you’ll be trying to prune while new growth is already happening, which makes it ten times harder.

Step 1: Identify the old canes. These are the ones that fruited this year. They’ll have side branches where the fruit clusters were. They’ll look more brown and woody than the new growth. Cut every single one of these down to ground level. Don’t leave stumps — cut right at the base, as close to the soil as you can get without digging.

Step 2: Thin the new canes. This is the bit most people skip, but it’s important. You don’t want to keep every new cane — if you do, they’ll be too crowded and the fruit will be small and poor quality. Select the strongest, healthiest-looking 6-8 canes per plant (or about 8-10 canes per metre of row if they’re in a row). Remove the rest. Cut out any that look spindly, damaged, or diseased. Keep the thickest, sturdiest ones.

Step 3: Tie in the remaining canes. The kept canes need to be tied to a support system — typically horizontal wires stretched between posts. Space them out evenly along the wires, about 10-15cm apart. This gives each cane maximum light and air circulation, which means bigger, healthier fruit and less risk of disease. Use soft garden twine or special clips — don’t use wire or anything that’ll cut into the cane as it moves in the wind.

Step 4: Tip the canes. In late winter (February-ish), go back and cut the tips off each cane so they’re all about the same height — roughly 150-170cm tall, or just above the top wire if you’re using a post-and-wire system. This encourages the cane to put energy into producing fruit buds along its length rather than growing taller. Plus it makes picking easier because the fruit is all at a reachable height.

Pruning Autumn-Fruiting Raspberries — The Easy Ones

If you grow autumn-fruiting varieties (Autumn Bliss, Joan J, Polka, All Gold), you are laughing. The pruning is as simple as it gets. In February, cut every single cane down to ground level. The lot. All of them. Don’t agonise over which to keep and which to cut — they all go.

In spring, new canes will grow from the roots, and these will flower and fruit in late summer and autumn of the same year. Because you’re cutting everything down each year, you never have the confusion of two generations growing together. It’s the ultimate low-maintenance fruiting system and honestly, if I was starting from scratch, I’d plant autumn-fruiters exclusively just for the easier pruning.

The only decision you might make is to thin the new growth in early summer if there are too many canes coming up. Remove the weakest ones and aim for about 8 canes per plant. This channels the plant’s energy into fewer, stronger canes that produce bigger fruit.

Pruning Blackberries — Similar but Different

Blackberries follow the same biennial pattern as summer raspberries — old canes fruit and die, new canes grow to fruit next year. But blackberry canes are much longer, more vigorous, and covered in seriously nasty thorns (unless you’ve been clever enough to plant thornless varieties, which I cannot recommend highly enough — my hands still bear the scars of pruning thorny blackberries, and I’m not being dramatic).

The process is the same: cut out all the old canes that fruited this year, at ground level. Keep the best new canes and tie them in. But because blackberry canes can be 3-4 metres long, the tying-in is more involved. I use the fan training method — spreading the new canes out in a fan shape along horizontal wires. This gives each cane maximum light exposure and makes picking much easier than fighting through a tangled mass of thorny chaos.

Some people use a clever separation system where they train the new canes to one side of the wires and the fruiting canes to the other side. This makes pruning dead easy because you can see at a glance which side is which. When the fruiting side is done, you cut it all out and train the next batch of new canes to that side. Next year, the other side fruits. It’s a bit like crop rotation but for canes.

Hybrid berries like loganberries and tayberries are pruned exactly the same way as blackberries. Same biennial system, same principles. Just watch out for the thorns on tayberries — they’re even worse than blackberries, if that’s possible.

Common Pruning Mistakes (And I’ve Made Them All)

Leaving old canes: The number one mistake. People leave the fruited canes because they think they might fruit again. They won’t. They’re done. All they’re doing is harbouring disease and blocking light from the new canes. Cut them out ruthlessly.

Not thinning new growth: Too many canes means too much competition for light, water, and nutrients. The result is lots of small, poor-quality fruit instead of fewer, bigger, better fruit. Be brave and thin them out. It feels wrong cutting away healthy-looking canes but the remaining ones will thank you.

Using blunt secateurs: Blunt cuts crush the stem instead of cutting it cleanly, which creates entry points for disease. Sharpen your secateurs before you start. It takes five minutes with a sharpening stone and makes a massive difference to the quality of the cut. I use bypass secateurs, not anvil ones — bypass gives a cleaner cut on live wood.

Not wearing gloves: Seems obvious but I’ve done this more times than I’d like to admit. Blackberry thorns in particular are vicious and the scratches they leave are the kind that sting in the shower for a week. Decent thornproof gloves are an investment that pays for itself on the first pruning session.

Pruning at the wrong time: Summer-fruiters should be pruned after harvest (late summer/early autumn). Autumn-fruiters in February. If you mix these up, you’ll either cut out canes that are about to fruit or leave dead canes sitting around all winter. Knowing which type you’ve got is step one — if you’re not sure, look at when they fruited. June-August fruiting = summer variety, pruned now. September-November fruiting = autumn variety, pruned in February.

After Pruning — Looking After Your Canes

Once you’ve pruned and tied in, give the base of the plants a good thick mulch with well-rotted compost or manure. About 5-8cm thick, spread around the base but not touching the canes themselves. This feeds the plants over winter and suppresses weeds in spring. I also sprinkle a handful of sulphate of potash around each plant in early spring — the potash encourages flower and fruit production.

Check your support system while you’re at it. Posts rot, wires stretch, and everything works loose over time. Much better to fix it now while there’s no fruit hanging off it than to have the whole system collapse under the weight of a bumper crop in July. I lost an entire row once when a post snapped mid-season. All the canes went over like dominoes. Absolutely devastating, and completely avoidable if I’d checked the posts in winter like I should have.

Look after yourselves. Take good care. 🌱