Plant Doctor Archive

Caring for my Magnolia

Question OUR Magnolia ‘Iolanthe’ is approx. 2 metres high and been in the garden 5 years. It flowers well each year but puts on little growth. Would pruning the lower branches off or any branches help it grow, and if so what time of year could this be done?

Answer I ASKED our resident arborist, Jim Antill, for his advice. Jim suggested looking at soil type and fertility first. Magnolias generally prefer rich, well-drained soils. If your tree is not in the right soil conditions, it could be sulking.

Cutting branches off may stimulate “juvenile” growth of upright branchlets, and these will not flower for at least a year. They also could become tangled with the more spreading habit of the older branches. Jim could not see much benefit as far as growth goes.

But if for other reasons there is a case for removing branches, do it in the dead of winter or very early spring before the buds begin to burst. Make sure that you don’t cut the “branch collar” at the base of the branch. This takes the form of a slight swelling, and consists of stem tissue, not branch tissue. If it is damaged, e.g., by making a “flush cut”, the tree is more susceptible to rot penetration.