How can you tell if your trees are healthy?

If all is going well with your trees this spring, you should be seeing growth like this on your trees:

New spring growth on an apple tree
New spring growth on an apple tree

This time of year we like (and expect) to see a flush of strong, healthy new growth in our trees, particularly on young trees.

Successful fruit growing is all about helping the tree to balance its energy between growing new wood (i.e., new shoots, as you can see in this photo of a young apple tree) and growing fruit. If it grows too much of one, it tends not to grow much of the other.

We need the new wood so the tree continually has new buds being formed to produce next year’s fruit (though the buds can also form on older wood in some trees).

But we don’t want the tree to put too much energy into growing wood at the expense of putting its energy into growing fruit – it’s a balancing act.

Shoot length is one of the best indicators of the overall health of your tree, and spring is the time to monitor it – so visit your trees and have a look.

If you see plenty of young vigorous shoots (anything from a few cm to 1 metre long, depending on the type and age of the tree), you know the tree’s pretty happy.

And if you’ve done a great job with your pruning, you’ll also notice that the new shoots are growing in the right place in the tree to make future fruit picking easy and manageable.

Here’s what healthy spring growth looks like in cherries:

On a young plum tree…

Healthy spring growth on two year old plum tree
Healthy spring growth on two year old plum tree

On a mature plum tree…

An Angelina plum tree showing vigorous spring growth
An Angelina plum tree showing vigorous spring growth

and finally, a mature apricot tree that’s growing beautifully (note the beautiful red colour of the fresh new growth, which will gradually fade through orange to green).

Beautiful new growth on a mature apricot tree
Beautiful new growth on a mature apricot tree

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!

Rude fruit

Have you seen any double fruit in your fruit trees?

A double cherry
A double cherry

It’s relatively common to see double fruit (like these cherries), and as you can see, in many cases the fruit is still perfectly usable.

The photo below shows a particularly unusual one that has caused the stem to split, but doubles – or conjoined fruit – are not an uncommon occurrence, particularly in stone fruit.

Conjoined apricots with a single stem
Conjoined apricots with a single stem

Some varieties (like Angelina) seem particularly prone to this, and are often a good demonstration of the phenomenon where one piece of fruit dominates the other and ends up much larger.

Conjoined Angelina plums where one plum is much bigger than the other
Conjoined Angelina plums where one plum is much bigger than the other

In many cases one of the pieces of fruit ends up so small as to really be un-usable, or the skin of the fruits are torn when separating them, which of course downgrades the quality of the fruit.

A rude Angelina
A rude Angelina

And sometimes the extra piece of fruit is so small as to be insignificant, and sometimes can be removed without doing damage to the main fruit. But they’re also often cute, funny or downright rude, so why would you?

So, what causes this, and is it avoidable?

Whether a fruit will be double or not is determined the summer before, when the fruit buds are developing.

If the young buds go through heat or water stress during the summer months, this increases the development of doubled fruit.

There’s not much we can do about heat waves, particularly with climate change affecting our environment so quickly, but we can make sure our trees are adequately irrigated, particularly during a heat wave, to minimise the stress on the tree.

Irregular or inadequate watering can also be one of the causes for fruit splitting, which is another whole story but can look like this.

A green nectarine with a split in it, possibly caused by irregular waterin
A green nectarine with a split in it, possibly caused by irregular watering

In a home garden it’s not terribly important whether you have double fruit or not because it’s usually still usable, but it’s not as pretty, and now you know how to avoid it! Download Smart Irrigation for Fruit Trees for more tips about how to irrigate wisely without wasting water or money.