You’ve probably heard that you’re supposed to prune fruit trees. But did you know that it’s also important to prune berries? Here’s Russell Norton, a horticulture and agriculture educator with Barnstable County’s Cape Cod Cooperative Extension — who offered me some tips, starting with high bush blueberries.
"The way that we generally prune blueberries is they're shrubs that often produce new shoots out of the ground. And it's really important to for almost all shrubs that produce shoots out of the ground to maintain youthfulness in the shrub."
This is because blueberries fruit on young shoots.
"So we generally want to have a couple one year old shoots, a couple two year old shoots, a couple three four and five," Russell explained.
"As they get older and bigger, we tend to remove them. And so you can kind of go into a blueberry bush and without thinking too much, you can go in with a pair of loppers and remove the two oldest, biggest stems. And you're probably doing good."
This is my kind of pruning — simple. The only caveat, Russell cautioned, is that you don’t want to remove too much of the plant at once.
"So there is this kind of like standard rule of thumb where you don't prune more than 30% of a plant. And that is actually a fairly kind of traditional and pretty good rule."
But of course, as with all rules, there are exceptions. For instance, fire. Blueberries can be pruned with pruning shears, but they’ve also been burned by people across North America as a form of rejuvenation pruning for thousands of years.
"If you're familiar with like little Bush blueberry production and, you know, the mountaintops of Maine and maybe even northern New Hampshire, that is a common practice. And that practice is really to maintain youthfulness."
In place where people burn blueberries instead of pruning, Russell said, they often divide up their blueberry land and burn each patch in rotation, once every few years, so that while some patches of land recover, others are still producing.
And when it comes to brambles — a thorny group that includes raspberries, blackberries, and black raspberries — the rules are slightly different.
"And so when we think about how the brambles grow, most of them they produce a primo cane the first year. So that's a shoot that comes out of the ground. It generally doesn't produce any fruit. And then it goes through a winter stage and then the next year becomes a flora cane. And so Flora cane meaning it produces flowers and then fruit."
Once a cane has fruited, its lifecycle is complete, and it will die back. So it flowers, it fruits, and then you want to remove it. But of course — you knew it was coming, didn’t you — there are exceptions.
"Some brambles are primo cane varieties where they will produce a crop of fruit on that first year's growth and they can be maintained as primarily primo canes in which they're mowed down at the end of the year and you get a fall crop every year."
To make matters even more confusing, some raspberries will produce on both flora — second year — and prima — first year canes —this is the type I have, and nurseries usually call them ever-bearing. others like blackberries and black raspberries do something called tip-rooting.
"A lot of the brambles will create aggressive long canes and if you allow them they’ll be arching and they’ll reach down to the ground and when they touch the soil they’ll start to root again."
I’ve always let this happen, but Russell said its better not to. If you cut the canes back instead of letting them sprawl, it encourages the plant to put more energy into flowers and fruiting — and less into stem length. It’s fascinating, getting to know all these berries quirks — and a good reminder that as always, giving our plants the correct care means paying attention to their behavior and their needs — which after all, is part of the joy of tending.
—
Watch a video about pruning blueberry bushes here.
