How Hard to Prune


When cutting back a shrub it is important to know the different effects that hard or light pruning have on the plant's subsequent growth. In general, hard pruning promotes strong, vigorous growth, whilst light pruning tends to produce weaker growth.

This principle can be used when pruning an unbalanced looking shrub; simply cut back the thinner side harder so that it produces more vigorous growth to fill in any sparse portions. Make sure the thicker side is only trimmed lightly.

You will also need to bear in mind that hard pruning existing vigorous growth will encourage even stronger growth. Therefore, it is a good idea to trim strong growth lightly and to hard prune weak growth.

Hard Pruning to Encourage Flowering

Whilst hard pruning may sometimes seem very extreme, many shrubs perform poorly and become straggly without it. For example, if a shrub that only flowers on the current season's growth is severely cut back in early spring to within approximately 5 cm (2 in) of last year's stem, then it will generate a host of healthy new shoots on which new flowers will bloom. Without pruning, there would be little new growth, and the plant would begin to produce fewer and fewer flowers - usually only at the very tips of the stems.

Hard Pruning to Renovate

Neglected shrubs can often be revitalised by pruning them back hard to approximately 30-45 cm (12-18 in) from ground level. The following year, there should be a mass of shoots produced below these cuts; two to four on each main stem should be retained to create the new framework. This work should normally be carried after flowering or whilst the shrub is dormant; however any renovation work should be delayed until mid-spring for evergreen plants. Always check the individual requirements of any shrub before pruning.

Hard pruning usually involves cutting the plant back as far as new growth; however, crowded and overgrown shrubs may be cut back almost to ground level to improve their overall shape.