Those of us with ‘maintenance gardeners’ are likely aware of how rare it is to find someone who knows how to maintain hedges properly. It seemed so simple years ago. Several identical plants could simply be planted in a row, and then somewhat regularly shorn for confinement to a prescribed space. They were not allowed to exceed a specific height or width for long between shearing.
Formal hedges are now passe. They do not conform to modern landscape style. No one wants to maintain their formality anyway. If a gap develops, it is likely to be filled with a different cultivar or species that is not identical to the rest of the hedge, merely because it happened to be available at the nursery. Feral or invading shrubs, vines or even trees get shorn right into the whole mess.
Then there is the problem with bloat. Rather than staying confined, hedges typically get slightly larger with each shearing. What is worst is that most of the extra bulk is high up and shading lower growth, causing it to grow slower. Hedges eventually develop that all too familiar top-heavy appearance, and encroach into otherwise usable space that they were designed to provide privacy for.
There are few simple options for hedges and shorn shrubbery that have gotten too big for their space. Some can be renovated and cut back beyond their outer surfaces, but recovery will take a bit of time, and can not fix unmatched plants. However, such restoration is likely better than replacement. Just like for a new hedge, feral and invading vegetation must be removed in the process.
Another option is to completely change the form of improperly shorn shrubbery to small trees. This can be done with individual shrubs, or a few selected remnants of an otherwise removed hedge. Cherry laurel, photinia, bottlebrush, tea tree, privet, various pittosporums and many other large hedge shrubs work quite nicely. Rather than getting pruned back into submission, the lower growth gets pruned away to expose sculptural trunks within, and the upper growth gets pruned only for clearance above.