Few fruit trees are pruned wrongly as often as the sour cherry. Many treat it like an apple tree and wonder why it bears less every year and only at the branch tips. The reason lies in a peculiarity that tells you everything about the right cut.
The sour cherry fruits on one-year-old wood. Whatever has borne once goes bare and never bears again. That is why it needs no timid shaping cut but a bold renewal. Understand this principle and you have full harvests for decades.
Why the sour cherry wants renewing
The sour cherry (Prunus cerasus) forms its fruit on the long, whip-like shoots that grew the previous year. After the harvest these whips hang down limply and are bare along their whole length, with new wood only at the tip.
Leave it that way and the harvest shifts further outward and upward every year while the inside of the crown goes bare. So you cut the spent whips back and steer the strength into fresh, young growth. This constant renewal keeps the tree compact and productive.
How to renew the sour cherry
Prune right after the harvest
Reach for the secateurs as soon as the cherries are picked, around CW 27 to 32. The leafy tree seals the wounds quickly, which prevents disease.
Spot the spent whips
Look for the long whips that have borne and now hang down bare. Fresh growth sits only at their tip.
Divert onto a young shoot
Cut the spent whip back to a well-placed young side shoot. This diverting is the actual renewal cut: the young shoot takes over and bears next year.
Thin the crown
Remove shoots that are too crowded, crossing or growing inward. Light and air in the crown dry the foliage and keep brown rot in check.
Cut cleanly and smoothly
Use sharp, clean tools and cut close to the base. On the warm, leafy tree, smooth cuts seal best.
What has borne goes bare. Divert the old whip onto a young shoot, and the tree stays forever young.
The core rule for the sour cherry
Frequently asked questions
Why does my sour cherry only bear on the outside now?
Because it fruits on one-year-old wood and you have not renewed it. The old wood goes bare and the harvest moves outward. Divert the spent whips onto young shoots and the yield comes back into the crown.
When do I prune the sour cherry?
Right after the harvest in high summer, around CW 27 to 32. Winter is the worst time, because open cut wounds heal poorly then and disease gets in.
What does diverting mean?
You do not simply cut off a long spent shoot but cut it back to a younger side shoot. That one takes over the direction and the cropping. So you renew the branch without leaving a bare end.
Is the sweet cherry pruned the same way?
No. The sweet cherry bears on several-year-old bouquet spurs and is only thinned, not so strongly renewed. But you prune both in summer after the harvest, not in winter.
Why not prune in winter?
Stone fruit like the cherry tends to gummosis and poorly healing wounds with a winter cut. On the leafy tree in summer the cuts seal quickly, and brown rot has fewer chances.
