[RosieMay]

Our plum tree is so laden with fruit this year it looks as if it could fall over!  It has become very tall and spindly and needs a really good pruning. It is about 5 years old.  How/when is the best time to do this?

[Pip Judgeford]

Hi RosieMay,

I live in a high silver leaf area (host trees such as poplar are common in my valley) and plums, especially the English types, are very prone to silver leaf.  So I dont prune in winter because the wet weather really encourages silver leaf & other diseases.

Instead I prune in summer, after all fruit are picked.  Sure its a little harder to see the structure of the tree.   Pruning on a sunny day in summer, when the weather forecast says there will be a couple more days of sun, is ideal. There are fewer disease spores etc around in summer and a fine spell means the tree has the very best opportunity to heal any small or big cuts before the wetter weather sets in.   I still use pruning paste or paint.

Summer pruning is a bit more tricky for apples than plums, as I have to decide whether sacrifice fruit in order to prune.  But plums fruit earlier and its easy to find a good pruning window.

To be honest the most useful paint is from those test pots where the brush is part of the lid - these are cheap (often minimal from a op shop or recycling centre) and you dont have to worry about keeping track of the brush!  Half my fruit trees are dobbed with "Santa's Beard"

The other thing to keep in mind is that in spring the tree vigour is determined by the tree's "memory" of how big the tree was at the end of the growing season.  Thus if you winter prune, the tree still thinks its huge and the roots therefore push out lots of top growth because they think they need to to reach the whole of the tree they remember from autumn.  This often means lots of growth but few flowers/fruit because the tree has no energy or inclination for fruit.

If you summer prune, the tree's memory of its size is its autumn size after you summer pruned it (ie a smaller tree).  So it pushes out enough oomph/vigour to reach the smaller size of tree and then uses the rest of its energy to make flower/fruit.

So summer pruning does it for me on two counts: less disease and less mindless vigour (thus more fruit.   

regards, Pip