Gardening with Daphne Ledward

A couple of readers have asked me recently whether it’s possible to prune a prunus “Ama-no-Gawa”.

This ornamental flowering tree, otherwise known as the flagpole cherry, has become popular in recent years as one that will fit into a small space, as its natural habit is to grow upwards rather than spread out.

It is therefore useful as an accent tree amongst smaller shrubs or perennials as its branches will not overhang anything planted close up to the trunk.

However, the flagpole cherry does exactly what it says on the tin.

It is not a small tree, even though it is often sold as a young one perhaps no more than a metre in height.

The one in our garden has been planted less than 10 years, yet it is already about 5m tall – and still growing – but is less than a metre in diameter at its widest point.

Its habit means that in a very small garden, the height may eventually be totally out of proportion, even though it takes up little space.

The answer, therefore, to the readers who want to know if their’s can be pruned is – yes, it will take even hard pruning without harm, but just reducing the height has two drawbacks.

The first is that the best feature of prunus “Ama-no-Gawa” once flowering is over is its slender shape, and just taking the top out can spoil this completely.

The other is that reducing the height will cause it to bush out to make a much wider tree, which often will not fit its situation.

Pruning an “Ama-no-Gawa” takes time and care, shortening back all the side branches severely before taking out the lead shoot or shoots.

Done properly, this will preserve the habit without allowing the tree to dominate, but, once pruned – in this or any other way – you will have to do it regularly as pruning encourages much more growth than is needed.

It may well be better, then, that once the tree has reached the stage where pruning is necessary, it is removed completely and replaced with something more suitable; for instance, the slow-growing fastigiate elm, Ulmus “Dampieri Aurea”, which, although not a flowering tree as such, has bright golden leaves from spring to autumn.