Thinning cherries … or not?

As part of our continuing series about fruit thinning, this week we’ll have a look at cherries, because we’re often asked if they also need thinning.

Tiny cherries in spring
Tiny cherries in spring

In fact, we recommend thinning all deciduous fruit (well, all the types we grow anyway) except for cherries.

In non-organic orchards, most thinning is done with chemicals, but in organic orchards and gardens we do it all by hand.

One of the most exciting parts of spring is actually at the end of the blossom period. It’s not always possible to tell just from how many flowers your tree has how big the crop will be.

Watching the flowers dry up and fall off your trees reveals the tiny fruit underneath, and it’s only then that you can really start to assess how big (or small) your crop will be.

Cherry flowers falling off to reveal the tiny cherries underneath
Cherry flowers falling off to reveal the tiny cherries underneath

Cherries usually have a pretty good crop most years – they are not as likely to have a heavy crop one year followed by a light crop the year after (which is called biennial bearing).

Plus, they grow on nice long stems, so don’t crowd each other out. It’s also pretty unusual to see branches or laterals in cherry trees breaking from the weight of bearing too much fruit.

In fact, most of the reasons we thin other fruit doesn’t apply to cherries, so that’s one job we don’t have to do!

Thinning to protect your tree

As part of our continuing series about fruit thinning (a very relevant topic in spring) this week we’ll talk about the second main reason we do thinning, which is to protect the structure of our trees.

A broken lateral in an apricot tree caused by to much fruit (or not enough thinning)
A broken lateral in an apricot tree caused by to much fruit (or not enough thinning)

Most fruit is carried on the small side shoots, or laterals, that grow from the main branches — they are a very precious part of the tree, and need to be protected. Left to its own devices, the tree will frequently set so much fruit on a branch or lateral that the weight of the fruit breaks the branch, as you can see in the photos above and below.

Too much weight has broken branches in this apple tree
Too much weight has broken branches in this apple tree

Our job when thinning is to remove some of the fruit that the tree has set, leaving only as much as any structural part of the tree can easily carry.

Bebeco apricots after thinining - not too much weight for the lateral to carry
Bebeco apricots after thinining – not too much weight for the lateral to carry

It’s important to imagine how large and heavy the fruit will be when it’s fully mature – as a very rough rule of thumb, a short lateral can only bear the weight of one piece of fruit, and a longer or stronger lateral can carry two or more pieces.

Tatura 211 peach after thinning - just one peach on the lateral
Tatura 211 peach after thinning – just one peach on the lateral

Of course the actual amount of fruit you can leave on the tree depends on many variables:

  • the type of fruit,
  • the variety (cultivar),
  • the ultimate size of the fruit at harvest,
  • whether the tree is heavy, medium or light crop,
  • when it’s due to be harvested,
  • age of the tree, etc.

It’s fine to just follow the rule-of-thumb guidelines we provide, or if you’re keen to protect your tree and in a hurry to get good results you can use the charts we’ve developed in the Grow Great Fruit program and the Fruit Tree Thinning short course to save yourself a few years of trial and error!

While you’re thinning…

It’s the time of year to start thinning your apricots, peaches, nectarines and plums (too early for apples and pears in our part of the world yet). We’ve explained the basics of thinning here.

Apart from the four main reasons you should be thinning all your fruit trees, it’s also just a great time to get out among your fruit trees, which gives you a chance to notice things like this.

A young apricot in close proximity to flowers that have died from Blossom blight disease
A young apricot in close proximity to flowers that have died from Blossom blight disease

There’s no thinning to do here – there’s only one apricot in this site, and it has plenty of room to grow during the season.

But while you’re checking all your fruit, you may notice instances like this where diseased flowers or shoots are touching the fruit.

It’s hard to see but the apricot is attached to the branch on the left hand side of the photo, and touching a diseased part of another branch on the right hand side that is covered with dead flowers infected with a fungal disease Blossom blight.

The disease that causes Blossom blight in flowers also causes Brown rot in fruit later in the season, so left alone, the fruit is very likely to develop Brown rot at the spot where the diseased flowers are touching.

A clean apricot with plenty of space around it to grow into
A clean apricot with plenty of space around it to grow into

So it’s super important to remove the diseased twigs either by pruning them out (it’s always a great idea to keep your secateurs in your pocket while you’re thinning) or just remove them with your fingers.

Doing a spot of summer pruning at the same time as thinning
Doing a spot of summer pruning at the same time as thinning. 
Photo credit: Biomi photo

Depending on your climate most peach, nectarine and plum varieties will have finished flowering by mid-spring and you can see whether or not they’re going to have a good crop and get the thinning well underway.

Though thinning is a crucial job in the lifecycle of your fruit tree, it’s also a quiet and reflective time to spend a dedicated half hour or so with your tree and having a really good look at what’s going on. Enjoy!