When do I prune my magnolia?
Q‘Our Magnolia x loebneri is growing rather large and the branches are shading out the plants beneath. They are also threatening some cables above. Can I prune it and if so, when?’
Eileen Beach, Wigan, Greater Manchester
AThis hybrid between M. kobus and M. stellata makes a lovely small deciduous tree for the garden. The various cultivars are unfussy and happy to grow in almost any well-drained soil, including chalk.
More upright and pyramidal than commonly planted M. soulangeana, their blooms open mid-spring and seem less prone to frost damage. Magnolias like a sheltered position away from wind and frost pockets, but the top of our tree survives regular battering by gales.
Popular pink-flowered M x l. ‘Leonard Messel’ and white Magnolia ‘Merrill’ will both reach around 25ft (8m) in height, but compact ‘Ballerina’ usually stops at 10ft (3m).
In small gardens, we do tend to cram plants in so that even small trees begin to interfere with cables and neighbouring plants. Although it is best to avoid pruning magnolias, they are forgiving of the considerate removal of the odd branch or two. This is best carried out in late summer and autumn, when the leaves are still on and the sap is not rising.
Always take pruning slowly, removing branches gradually back to the older wood; you can always take off more, but you can’t stick branches back on! Avoid chopping at stems halfway along, because this tends to encourage a lot of thin ‘water shoots’ that will spoil the look of the tree.
Use secateurs and loppers for smaller branches and a foldable pruning saw for the larger ones. Access higher branches using a safe step ladder, with someone at the base to hold it steady, as well as a long-handled pruning saw – or, in extreme cases, hire a tree surgeon to carry out the work.