Monday, 17 November 2014

Espalier Pruning

Sometimes it is just good to leave plants to their own devices rather than prune them unnecessarily. However, if you are pruning to make and maintain a particular shape such as cordon or espalier then it is unavoidable.

So if we follow the RHS advice, and I rarely do that, pruning involves 3DXU, which stands for dead, diseased and damaged; crossing and untypical.

Once these factors have been dealt with then we can concentrate on the form of the plant and what we want it to look like.

Pruning long produces massive amounts of new growth.  In other words if you cut large chunks off trees it promotes the production of long stems or branches.
Willow sculpture.
The willow in this sculpture has been pruned long and has thrown up multiple new stems showing quite clearly what pruning hard does to trees.

This kind of growth on fruit trees like apples and pears is not fruitful.  What is needed are the small fruiting spurs which develop on mature wood and, to encourage these to form, we prune short. Pruning short is just taking off the ends of branches to a maximum of about five buds leaving the rest of the branch to mature and throw off fruiting spurs the length of the stem.  

So, if the tree throws up vigourous stems during the summer, like the willow in the photograph, cutting the branches long will just encourage more long, fruitless, whippy branches. Sorting out this confusion will be a time consuming winter task.  

There are several ways of dealing with vigourous growth.  If it is in an area of the tree that needs a new branch it can be pruned short taking the end off the branch by about five buds. If pruning to espalier or fan, branches  can  be tied in during the summer and  lowered into their fruiting position in the winter.    Lowering vigourous branches to the near horizontal will slow their growth and help them produce fruiting spurs. Weak stems, that could fill spaces, can be tied in vertically to encourage them to grow more vigourously. Usually the lowest branches seem to be the weakest and these can be strengthened by leaving them to grow as upright as possible until they attain length and vigour enough to be tied in horizontally.

Sometimes vigourous growth needs to be cut back to the collar next to the main stem in the summer.  If this has to be done to prevent confusion, then new buds that will inevitably be produced should be rubbed off after they have pushed their way through the bark.   Similarly any woody branches that grow away from or towards the wall should be removed.

When we are trying to produce an espalier, we want branches to be produced at regular intervals along the main stem.  When two horizontal, lateral branches have been produced near the bottom of the tree that can be tied in to the left and right, the main stem can be cut back long to 4 or 5 buds to produce two woody laterals that can be tied in the next year.  One bud can be allowed to grow on vertically to produce a stem, which can provide the next years laterals. Superfluous growth can then be cut back long to their main stem collar.  The horizontal laterals should be about a hand span apart to allow light and air to get to the foliage and fruit.

The horizontals can be left to grow on without any pruning until they fill the space allotted to them. Only then will they have to be pruned short.    

A combination of good sensible cuts and raising and lowering branches will produce a good looking, espalier tree that is very high yielding.

1 comment:

  1. Roses, to prune or not to prune. Well pruning is a must, especially on these Knockout roses, a poor man's introduction to the family Rosaceae. I resisted pruning hard last year (or the year before that) to my detriment, the roses are too leggy. However, having held off on most of the roses until the first frost occurs, I did prune two plants some three weeks ago and I'm encouraged by the fact that each stem is yielding new buds. My fears seem to be unfounded, so I'll go ahead and attempt to improve the aethestics.