How to Prune Hedges like a Pro

The best tips and tricks to prune your hedge for optimum health and longevity

Gardeners and landscapers have been using hedges for centuries to create beautiful, thick borders. Some are tall for privacy and security, while others are small and compact for lining paths and planting areas.

Defining characteristics of hedges are that they are rows of trees or shrubs planted fairly close together that are repeatedly pruned or sheared to create uniform rows where individual plants can no longer be identified. Any type of shrub or tree can be hedged, but some are more popular since they respond better to the repeated pruning.

Pruning is really the key to creating a hedge, and doing it correctly can lead to a hedge that survives for hundreds of years, while doing it wrong can result in a hedge that is destroyed and needs to be replaced in a matter of a few years.

Why is pruning so important? There are several reasons.

The first is that a pruned hedge is a healthier hedge. Since plants are grown very close together in a hedge, it takes extra care to provide ample light and air flow to the plants. Pruning to a narrow width helps with both of those things. Damp, dark conditions lead to sparse growth and diseases, so pruning helps keep hedges healthy.

Second, a pruned hedge is tidy and beautiful, forming a solid and breathtaking wall of green. If pruning is not done correctly or consistently, you can end up with a leggy hedge with unattractive bare spots. Pruning can also dramatically change the style of the hedge – imagine a clean, perfectly squared hedge with its modern lines compared with the soft, undulating lines of a hedge that has been pruned in a rounded form. Different pruning styles can make a big impact on the garden style.

Finally, the third thing that makes pruning important is how it extends the longevity of the hedge. A hedge that has bee pruned well from a young age is a hedge that will last for decades and beyond. A hedge that is poorly pruned is prone to develop bare patches, ugly areas, or worse yet, disease that spreads rapidly through the whole hedgerow. All these will result in either the death of the hedge or its becoming so sparse or unattractive that its usefulness ends. Hedges are an investment of time and money, so it is in your best interest to keep them beautiful and healthy for many years. One thing that can help is starting with a pre-finished hedge that has already been pruned for 5 years. This is easier than starting from scratch with individual plants, as you simply need to continue the lines that have already been started for you.

So what is the best way to prune a hedge to keep it thriving and attractive? The method varies slightly depending on the type of hedge. It is quite simple and is easier when it is done more consistently.

Pruning evergreen hedges (types that do not lose their leaves in the winter) is best done in spring or fall, or both if needed depending on the growth rate. For fine-textured evergreens like Yew or Arborvitae, electric hedge trimmers are very effective. For broadleaf evergreens like Cherry-laurel, hand pruners can help reduce the amount of damage to the leaves but that is only a cosmetic issue.

Pruning deciduous hedges (types that do lose their leaves in winter or the leaves are dead but hang on the branches until spring as with Fagus Sylvatica) is best to do once in winter when the branches are bare or just have dormant leaves. This helps you see the structure of the hedge and minimizes stress on the plants. If the hedge is a fast grower, you can also do a light trim in the summer to even out the shape, but do this carefully with hand pruners to avoid leaf browning. Hand pruners are generally best for deciduous hedges but in winter electric trimmers can be used.

5 key tips to remember:

1. You can prune non-coniferous hedges hard and it will only make them better. A coniferous hedge like Arborvitae cannot be pruned back into old wood or it will leave bare spots. Conifers do not have as many “latent buds” as other types of hedges, so they lack the ability to back-bud. Prune them consistently and you won’t have any problems.
2. Always use sharp pruners whether you are using hand pruners or electric hedge trimmers. Dull blades can mangle branches and leaves and are much harder to use.
3. Go slow. Prune for a few minutes, then stand back and evaluate. Are you following the straight line of the hedge? Careless cuts can’t be undone.
4. Prune the top half of the hedge slightly narrower than the bottom to allow more light to reach the lower branches. This will keep the hedge full and lush all the way to the ground.
5. Cleanliness – clean up the branch trimmings as well as you can, especially when pruning a boxwood hedge. Branches and leaves can harbor disease when left in piles on the ground around your hedge, and the disease can then spread to your hedge. It is also important to sanitize your pruner blades before and after pruning, and when you move between different sections of hedge. Rubbing alcohol is an inexpensive and effective way to do this. Remember that hedges are in very close quarters and any disease picked up by one plant in the row will quickly spread to the rest. Be careful about sanitation and you will be fine.

Pruning a hedge may seem intimidating, but you can do it! Just pick a day with nice weather and go for it. It can be very relaxing and therapeutic, and you will get such a sense of satisfaction when you look back at your beautiful work.

About the Author: Stephanie Pratt is a lifelong gardener. She received a BS in Horticulture from Oregon State University with an option in Plant Breeding and Genetics. She has worked in the nursery industry for her entire career and currently works as a hedge expert at InstantHedge in Oregon.