Hi, what’s the best practice to prune an overgrown privet hedge that’s over 70 years old? The hedge has grown fat and tall with most of the branches look dead inside, only the thin outer layer grow leaves. I have tried to prune a layer of exterior branches, but as the inside ones are so leggy they become top heavy and start to flop over. Online search suggests that a renewal (rejuvenation) pruning is necessary – cut the hedge down to 6 inches to a foot off the ground in early spring, let it grow back and then reshape it. May do it in phases as the work is pretty overwhelming. Is it the right approach?
Thank you for contacting Toronto Master Gardeners.
Privet (Ligustrum spp.) is a shrub originally imported from Asia and has an invasive nature, as birds spread its fruit and seeds. To manage your overgrown privet hedge, a radical pruning approach may be in order. As the British say of this shrub, “it’s as tough as boots” and regenerates by sending up sprouts from its roots and stump.
Privet can be cut down to about 6 inches above the ground in its dormant period. Late winter or early spring is ideal as long as no new growth has occurred. After cutting it down, apply a slow release tree/shrub fertilizer and mulch. Water frequently and when new growth occurs during the season, thin and reshape.
Once the growth reaches your preferred height, trim it into a shape that is broader on the bottom as in the diagram below.
Toronto Master Gardeners website has Gardening Guides on evergreen, native and ornamental hedges and growing tips for all different types of shrubs. For new or replacement hedging, it’s always wise to consider using native shrubs. Native selections are hardy, support wildlife and are not invasive.
As you mentioned, pruning old wood on shrubs is hard work. You didn’t mention the length of the hedge, but if pruning is done in phases, it may result in varying levels of growth, in different parts. Use appropriate, sharp tools and maybe get some help, if the hedge is extensive. Landscape Ontario https://landscapeontario.com/ is a reputable organization who could advise you on hiring assistance. More information on pruning tools and practices are available on the websites below.
Hope your privet hedge renewal is a success.
https://extension.psu.edu/privet
https://extension.umd.edu/resource/pruning-shrubs-and-hedges-home-garden