Right about now, I’m starting to think about pruning my autumn-fruiting raspberries. They’re good old ‘Autumn Bliss’, rock-solid reliable, heavy cropping and utterly delicious. They came into their own this year, their second in my garden: I confess not many made it as far as the kitchen, as I find a fresh raspberry irresistible, but I’m hopeful that next year they’ll be even more prolific and we’ll have enough left over after my frankly greedy forays into the fruit cage to start producing raspberry icecream, summer puddings and even jam, maybe. Can’t wait.
They should be even more productive as they’re now on a double-cropping regime. Sounds fancy, doesn’t it? If you ever want to play old blokes with flat caps on allotments at their own game, drop the phrase casually into conversation, preferably in the same sentence as ‘double-U cordon’, ‘Guyot system’ and ‘festoon’ (as in apple trees), and finish off with a balanced analysis of the comparative merits of chip budding vs whip grafting. About halfway through, watch their eyes start to glaze over. But they’ll never complain about all these wimmin invading the allotment site ever again.
Anyway. Double cropping is actually a lot simpler than it sounds. As I’ve mentioned before, it’s also been tried and tested, and proved well worth doing. A few years ago, Which? Gardening carried out a proper trial on double-cropping raspberries and came up with some surprising results. They grew seven different varieties and pruned one row of each variety as normal, but double-cropped a second row.
On comparing the results they found all but one increased their yield (the exception was ‘Brice’, which showed a slightly lower yield with double-cropping). In some cases – ‘Autumn Bliss’, ‘Sugana’ and ‘Autumn Treasure’ – double-cropping produced twice the yield; and even famously high-yielding types like ‘Joan J’ gave nearly a kilo more raspberries over the season.
Feed and water your canes normally and Which? also say they shouldn’t become exhausted by fruiting for several months longer than they would do otherwise. Same workload, plants happy, double the raspberries: what’s not to like?
So now that I’m about to take the snips to my raspberry canes I thought I’d explain in more detail how you go about it.
1: If you’ve just planted your raspberries, leave them to grow and establish for at least a year before you start pruning at all (let alone double pruning). You’re ready to start pruning after they’ve produced their first good crop.
2: Start around now, late autumn/early winter, with autumn-fruiting raspberry canes which have just finished fruiting. Normally you would cut these right down to the base, every single stem: but instead of doing that, pick only the stems which have fruited and leave the rest untouched.
3: Your unpruned stems now have a head start on the stems which shoot from the base in spring, and by summer they’re ready to flower and fruit a month or so earlier – giving you a crop of ‘summer’ raspberries from your autumn-fruiting variety.
4: Meanwhile you have a little thicket of new stems shooting up (just as they would have done under conventional pruning). These will start to fruit at the normal time (August-September) – just as the first batch are finishing.
5: While you’re enjoying the second harvest, cut back those which fruited in summer just like you would if they were summer-fruiting raspberries. They’ll be replaced by new shoots which appear before the year is out; leave this intact when you’re winter-pruning the stems which fruited in autumn and the cycle starts all over again.
Well, that’s the theory anyway: I must confess that my overenthusiastic raspberries produced such a lot of fruit this year that very nearly every one of the canes has borne some berries. This means I’ve only been able to leave two or three shoots behind to carry on into next year. My guess is that this double cropping malarkey takes a year or two to get into its rhythm; I shall report back.