Tuesday 16 October 2012

A Pruning Class

Restoration pruning of my small tree

Bob Crow was the ‘artist in the garden’ 
at my recent open day. His picture gives 
a better image of my pre-pruned tree 
than any photograph. Two little girls, 
Olivia and Eliza helped Bob with his picture, 
he advised them to watch my blog to see 
their handiwork.
On the pruning course that I used to run at Harlow Carr Gardens in Yorkshire, I would include the following points: 
  • Don’t be scared of having a go, shrubs are tough, you will do them little harm.
  • Any harm is likely to be aesthetic: when you have finished pruning, your work should not be obvious to the casual observer!
  • Pruning cuts should be within the complete volume of the bush: if your cuts are all on the edge you have done it wrong.
  • As you become more confident you should take out big pieces, not lots of little ones. 
  • Restoration pruning of old shrubs can be done at any time of year. Even if some flowers are lost, those that remain on your now elegant shrub look so much better than they did before.
  • Never leave bare stumps at the end of pruned shoots.
Ten years ago my sophora was planted as a shrub 30cm high. Some plants do have a tendency to grow! Formative pruning changed as the shrub became bigger. If you allow it, what was a multi-stemmed shrub will, over the years, become a small tree. My tree threatened to become unsightly so one of the two remaining trunks had to go.

Heavy branches should be dismantled before making the final cut.
The last cut should be at the base of the branch leaving a natural shoulder. It should NOT shave into the main trunk. But why is it black?
After removing the large secondary trunk, a large branch high in the tree spoilt the new outline. It had to be cut back to a new leading branch. I can best illustrate the principle with this much smaller shrub.

A leading shoot grows over my lawn.
Cut it out to a new leading shoot.
Three weeks later it is still alive!

And did my pruning pass the ‘casual observer’ test?

I had rubbed soil on the wound to disguise the large white cut (this is not so silly, a common soil bacteria, Trichoderma viride, is antagonistic to wood decay fungus). 

Brenda returned from her holiday, walked the garden and saw nothing!  Fortunately she approved when I confessed.


  1. Pruning - well after much experience of this I believe it is all to do with personal aesthetics and little to do with horticulture.

    To you- a tree seems to need a single distinct stem - but why?

    The person who clips all their shrubs into uniform tidy blobs is just expressing their own idea of good practice and beauty. Are they any less "correct" than the gardener who prunes "to form" or the one who never prunes? Does nature ever prune except by random accident?

    1. I agree with what you say John, their are many forms of pruning and in one short article can only start out on a very big topic. I am intending more posts on pruning. Sometimes my pruning will be very different and even done by a hedge trimmer-and not just hedges!
      There is no reason whatsoever for a tree to just have a single stem. In my case, part of my decision was based on my tree's function in the garden and also that it was overgrowing other shrubs.
      I think I would agree with your first sentence more if you substituted the word 'nature' for 'horticulture'.

    2. OK nature if you like. But there's no denying there are many qualified horticulturists and horticultural books that give the distinct impression that there is a "proper" way and a "wrong" way to prune everything. I am not so sure I would agree with that!

      However I would agree that there is plenty of scope for opening peoples eyes to possibilities, methods and different ideas of beauty.

    3. I would not want folk to think that we are arguing about this, I think we actually are almost in total agreement! I can think of many plants that I prune in different ways and depending on where they are and their garden function my method will be different. Also and very significant some shrubs and trees should not pruned at all.One of my reasons for writing this blog is to challenge wrong information in some gardening textbooks and more especially certain magazines.

    4. Yes, I think we do agree. Certainly more plants are ruined by bad pruning than not being pruned at all.

      It is often to do with aesthetics or complete lack of! Also psychology?- a fear that plants will "get out of hand" and of losing control of them (or worse that the neighbours perceive they have lost control!).

      This fear is exploited ruthlessly by those awful "lopper and topper" gangs who roam suburbia mutilating trees. I once had a superb tall spire - like mediterranean cypress that one such oaf offered to top for me. I was almost too speechless to reply!


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