Ask any classically trained horticulturist, and they’ll tell you – hedges are bad. Why? This approach to plant care runs afoul of all of the proven plant health techniques that are used in gardening. Perhaps the most obvious is the strong recommendation against “topping” a tree, which involves making indiscriminate cuts in the stems at a predetermined height, which leads to the onset of decay and poor branch structure. Shearing a hedge is exactly the same technique with exactly the same results.
While the above is certainly true, there may be rare instances where an exception makes sense. For example, if a subdivision is named “Hedge Creek”, or was developed by Jim Hedge, then maintaining one row of plants in a neatly trimmed hedge would fit, even though it would be a high maintenance item, with lots of potential for defects and low aesthetics. So, if your mother’s dying wish was to grow a hedge in her honor, there are techniques that are better than others.
First, the bad techniques:
Use a hedge shears to make long rectangles of growth. This will result in the top of the hedge being wider than the bottom over time, as the top of the plants are exposed to the most light and therefore grow better than the bottom of the plants, which are shaded by the top.
Use dull hedge shears. This results in ragged cuts of the stems, eventually leading to pathogen invasion and death of the stems.
Grow several hedges in the landscape. This results in the need for repeated shearing of many specimens, which increases the odds of damaging the stems beyond repair or regrowth.
Instead, use these techniques:
Use a hedge shears to make the top of the hedge narrower than the bottom. This allows the bottom stems to be exposed to light for a longer period of time, keeping them healthier than the rectangles above.
Use sharp hedge shears. Sharp tools cut cleanly, allowing the stems to recover quickly.
Grow only one hedge in the landscape and prune by hand, not with a shears. This greatly reduces the need for repeated shearing of many landscape elements, and decreases the overall decay potential of the plants. Growing fewer hedges also increases the airflow through the landscape, encouraging drying of the leaves, resulting in lowered foliar disease incidence.