Winter pruning fruit trees

Beppe pruning plum trees in winter
Beppe pruning plum trees in winter

Have you started your winter pruning? If the leaves have fallen off your apple, pear, plum, peach or nectarine trees, now’s the time to get started. 

We talk a lot about pruning (it’s one of the main things that worries home growers), so we thought we’d share some basic pruning terminology.

Here’s how we label various parts of the tree:

A two year old plum tree that's had it's winter pruning
A two year old plum tree – still in the establishment pruning phase – that’s had it’s winter pruning

Limbs/branches, sometimes called ‘scaffold’ branches: these are the permanent, structural parts of your fruit tree. We usually recommend pruning your trees into a ‘vase’ shape, with between 6 and 10 limbs, starting from a central point about knee height above the ground.

The photo above is a young plum tree that only has 4 limbs, but has been pruned back hard to encourage more limbs down low in the tree (‘establishment’ pruning). We explain this technique, and the principles behind how a fruit tree likes to grow, in much more detail in Pruning Young Fruit Trees.

Of course your tree may have a different shape, e.g., espalier, central leader, or more of a wild and possibly completely unpruned shape (those last ones are pretty common!).

Laterals: these are shorter pieces of wood, also called small branches, side branches, shoots or twigs, that grow from the limbs. These are the main fruit-bearing parts of the tree. Strictly speaking a lateral just refers to one-year-old wood, i.e., the shoots that grew in the summer just gone, but to keep things simple we use laterals to refer to any growth coming from a limb.

Spur: this is a collection of buds, mainly fruit buds but also leaf buds, on a lateral, some of which may also turn into new shoots. The older a spur is, the less likely it is to generate new shoots.

Some fruit trees are much more prone to developing spurs than others, e.g., pears, some apples, and some plums. Apricots can also form spurs. The spurs can keep bearing fruit for years and require little pruning. If they are getting too crowded it’s OK to do some ‘spur pruning’ to thin them out a bit.

Buds – fruit trees have fruit buds (which turn into flowers), leaf buds (which turn into leaves and shoots), and multiple buds that are a combination of the two.

Fruit buds tend to be fatter and a little furrier looking, and leaf buds tend to be flatter and less significant.

Understanding which part of the tree we’re talking about makes learning how to prune much easier, so next time you’re gazing lovingly at your fruit tree, make sure you can identify all its different bits!

Frost and fruit trees

The question of frost and fruit trees often comes up when people are deciding which fruit trees to order for their garden, so we thought we’d clarify the issue this week, particularly as we’ve had the first few frosty mornings here on the farm.

A frost near the apricot orchard
A frost near the apricot orchard

Winter frosts are not a problem – in fact most deciduous fruit trees need a certain predetermined number of hours of cold each year to help them set fruit (this is called chill factor, and is a separate issue to frost – find out more about both chill factor and frost in this online short course).

Frost is only a problem for your trees in spring, and only if there’s a frost when the trees are flowering, or when the fruit is tiny just after flowering.

Spring frosts while trees are flowering can sometimes cause damage
Spring frosts while trees are flowering can sometimes cause damage

The hierarchy of frost-sensitive fruit trees is that almonds and apricots are most frost sensitive, then cherries, peaches and nectarines, apples, plums, and pears, in that order.

That doesn’t mean that apples, plums and pears don’t get frost damage though, they can. This is a photo of a typical ‘frost ring’ on a tiny pear – damage caused by a frost when the tree was flowering.

A frost ring on a pear
A frost ring on a pear

If you get bad frosts and don’t have a way to protect your trees in spring, then your apricot trees are likely to not bear fruit very often because the flowers will be burnt off by the frost.

This means they then put all their energy into growing wood instead of fruit, and you can end up with a very big tree!

A very large apricot tree
A very large apricot tree

So what can you do?

First, it’s important to know how frosty your place is, and where are the most vulnerable spots, so the next time you have a frosty morning, head outside nice and early in the dressing gown and gumboots, and really have a look at exactly where the frost is lying.

Then, try to match the trees you’d like to grow to the available micro-climates (saving the least frost-affected spots for the most frost-vulnerable trees).

Next, think about how you can create or enhance the microclimates
with plantings or infrastructure to create protected pockets.

Other things you can do include:

  1. Planting the most sensitive fruit trees in pots so you can shift them to protected spots in spring;
  2. Use frost cloth (or even old sheets) when frost is threatened (but remember to take it off again the next morning).
Frost on the soil
Frost on the soil

When you consider all the options available to you, it’s really surprising just how much you can do to provide the right habitat for lots of different fruit trees, even if they’re a bit outside their normal comfort zone.

This tamarillo tree is a great example – it’s absolutely thrived in a climate that is supposedly far too cold for it, by planting it in a sheltered spot right next to our shed wall.

A fast-growing tamarillo tree protected from frost by planting next to the shed
A fast-growing tamarillo tree protected from frost by planting next to the shed

Consequences of netting

Most decision in farming (and gardening) involve weighing up the pros and cons, and this even applies to netting. You’d think it would be a no-brainer – put on the net and save the fruit, right?

Well here’s one of the downsides, which becomes obvious when you take the drape nets off.

A peach tree bent from the weight of the net
A peach tree bent from the weight of the net

It’s a great lesson in why it’s best to remove the nets as soon as you’ve picked the fruit, and while the trees still have leaves on them.

This is a 4 year old peach tree, which grew very well this year and yielded a lovely crop of peaches.

It was netted it in plenty of time to save the fruit from the birds, and what should have happened next was the removal of the nets. But, things got busy, it never quite got to the top of the ‘to do’ list, and you can see the consequence in the photo above.

Abi and Hugh removing nets - in winter!
Abi and Hugh removing nets – in winter!

All the growing tips (or “leaders”) at the top of each limb have grown bent over. If they’ve been held down by the net for too long while they’re flexible and growing strongly, they may have permanently taken on that bent shape and won’t spring back into shape.

There are two things we can take from this:

  1. It’s not difficult to correct – some careful pruning at the top of the limbs will usually remove most of the bend and this will help the limbs continue their growth in a mostly straight line next year.
  2. Notice how easy it is to influence the way a tree grows, so if you’re aiming for a particular shape of tree (espalier, for example), it’s not difficult to encourage the tree to grow the way you want it to. Find out more about how to create espaliers, vases, and other fruit tree forms in Pruning by Numbers: A Guide to Pruning Deciduous Fruit Trees.

That’s the silver lining in this particular cloud!