We'll show you how to create the perfect hedge

Building A Hedge - Part 1
A Primer On The Basics Of Hedging
by Jim Kohut, Staff Writer

When it comes to landscape elements, almost everyone knows what a hedge is. Hedges are common to many of our northern landscapes and serve many useful purposes. When done right, they can greatly enhance not only the beauty but the functionality and livability of a landscape. But when done wrong, they can look downright shabby, and can quickly become a liability.

By formal definition, a hedge is a row of uniformly sized shrubs planted close together, particularly when they form a fence or a boundary. More informally, a hedge can be considered as any collection of identical shrubs arranged in some manner of order, which have been purposefully placed together to form some sort of barrier or boundary in a landscape. Almost all agree that hedges are usually free-standing on both sides; otherwise, they are better described as a border planting or garden.

Many homeowners desire to plant a hedge in one application or another which they serve so well. And yet, simple as it may seem, too many homeowners get them wrong. For that reason, we’re going in depth with a two-part Info Sheet which will instruct you on the basics of hedges, and guide you to building your own hedge the right way.

In this first part, we’ll take a look at the functions that hedges serve in the landscape, review some of the types of hedges, and explore some of the finer hardy plants available for hedging in the North. In the second part, we’ll see how to design and install your hedge. So sit back and get ready to do your hedge the right way!

	This low informal hedge creates a sense of enclosure for this backyard patio

Using Hedges In The Landscape

Hedges are one of the most fundamental applications of plants in the landscape. They are the living equivalent of a solid wall or fence in the realm of hardscaping, and therefore serve pretty much the same functions. Unlike solid walls, however, they are dynamic and flowing, and are much softer in their impact.

They are the ideal element to delineate boundaries in the landscape. They can mark off property lines, borders between outdoor rooms in a landscape sense, walkways, driveways, gardens, and more. Like walls, they send a message that this particular functional space ends here, and another one begins on the other side, with the two being separate and distinct. They can be both a physical barrier, keeping people on the paths and cars on the driveway, and a visual barrier, clearly implying that they are not to be crossed.

Hedges are very often used for screening applications. They can screen out undesirable views onto adjacent properties, and they can block noise from traffic or other sources. They can also screen views from the outside of your property in; screening can create private spaces for you and your family that are pleasantly isolated from the rest of the world. They enclose areas, giving the sense of a human scale to an outdoor room and functionally isolating it from areas with other functions.

Knot gardens are extremely stylistic applications of formal hedges

Very importantly to northern gardeners, hedges can be used to modify the local climate and create favorable microclimates. They block frigid winter blasts and the drying summer winds, which actually raises the ambient temperature in their immediate vicinity, permitting “out-of-zone” shrubs and perennials to survive the winter in regions where they may otherwise not stand a chance. They can also trap snow over the winter, which acts as a beneficial insulation to these tender beauties.

Hedges are also an important part of stylistic landscape constructions, particularly those reminiscent of the formal English style. They are an integral part of Victorian gardens, bounding the pathways and providing the rigid geometries of this style. They are also used to create knot gardens, their low tightly pruned forms weaving and snaking around each other in intricate patterns. And they are the mainstay of living mazes and labyrinths. Versatile, aren’t they?

Different Kinds Of Hedges

Hedges can be differentiated by their height. In the majority of applications, hedges are sized according to the requirements of the function in the context of human scale. So, a low hedge would be in the 1 to 2’ range, a medium sized hedge would be in the order of 3 to 5’, and a tall hedge would be anywhere from 6’ to a dozen feet or more. Medium-sized hedges are the most common, as they serve the basic functions of guiding and delineation. Low hedges are primarily used for their visual effects and for specific purposes such as knot gardens, while tall hedges are generally used for screening.

There are two basic styles of hedges; formal and natural. Formal hedges are those that are pruned to a specific shape, looking for all purposes like walls built of plants. Natural hedges are those in which naturally shapely plants are allowed to grow to their natural forms, but which are placed close enough in proximity to each other that they still function as a hedge. They are sometimes pruned for neatness and balance between plants, but they are never formally shaped. Formal hedges tend to fit specific styles such as the English gardens, while natural hedges are more suggestive of a modern design.

	The English Garden style hedge is strongly linear

Hedges can be constructed in many different ways. They can be arranged in a row in a perfectly straight line, or they can be staggered. Hedges may also consist of two or more rows of plants, the same plants if depth and density is desired, or sometimes different plants of differing heights, akin to a tiered garden border along a fence. They can be densely planted for optimal pruning or use as a physical barrier, or loosely planted if they are serving a primarily visual purpose. And hedges in rigidly straight lines are only mandated by certain styles; hedge rows can also wind and weave or form unique geometric shapes.

There are functional and there are visual hedges. Functional hedges are constructed to serve a physical purpose, for example preventing access to a different area or keeping people along a path. These are usually densely planted and of enough height to actually keep people from stepping over them. Visual hedges on the other hand are meant to be suggestive of their function, for example a low hedge that defines the boundaries of a garden or an outdoor room. Sometimes even just a few shrubs strategically planted loosely together in an otherwise open area will give a visual cue that the particular space ends there.

Selecting Hedge Plants For The North

So how does one go about choosing the best hedge plants? From the discussion above, it’s clear that the specification for hedging plants is derived from the end application. If it calls for a dense planting, you’ll need plants that are naturally dense. If pruning is required, you must select plants that are readily able to regrow branches from deep pruning cuts while still maintaining their density. Tall hedges need plants that get to an appreciable height in enough time, and short hedges require smaller plants that won’t overgrow their space in time.

Hedging plants are almost always shrubs, as by definition most trees are too tall and lanky to be used for most purposes. I’ve seen some trees such as Siberian elm and blue spruce used as hedging, but this is a gross misapplication of these fine trees; they do not enjoy being harshly pruned to grow against their natural forms and can be short-lived as hedges, not to mention the incredible degree of maintenance they require to keep them in form.

Dwarf Korean lilac in full bloom as a natural screening hedge

Many hedge applications can be rather demanding on plants, asking them to tolerate the abuse of being a physical barrier, using them to modify climates, and continuously chopping them down to keep them in a tight formal shape. This means that hedge plants should be vigorous, durable and tough - softies need not apply for this role. And of course, here in the North, hedging plants should be hardy; you don’t want every third plant in your row dying because it was living on the edge!

A specific note of caution is in order here. Many people desire formal trimmed hedges, but with the beautiful fragrance and color of flowers. So why not just construct a hedge using flowering shrubs? The trick is that the majority of flowering shrubs bloom on wood that was developed the previous summer or fall. Any branches that are pruned or trimmed between the time the flowers are formed and the bloom time represent lost bloom. If enough of the new branches are removed, there will be no flowers at all. So while lilacs, privets and viburnums make wonderful hedges, pruning them all but ensures that they will not be blooming the coming season. Save these for natural hedges.

With this in mind, there are a number of popular hedging plants that we can use here in the North, and some that merit additional consideration;

Boxwood (Buxus spp.) - The king of hedging plants, and by far the most popular around the world. It takes pruning better than any other landscape plant, and comes in all shapes and sizes. Unfortunately, it’s a broadleaf evergreen, and it’s not a reliable performer in cold-winter areas. It’s fine in zone 5 and warmer, a couple of cultivars will do OK in zone 4, but forget it in anything colder.

	Globe cedars make a spectacular untrimmed hedge

Alpine Currant (Ribes alpinum) - The ubiquitous hedging plant where boxwood isn’t reliable. All the charm, durability and density, except that it’s deciduous, and it’s generally a smaller plant. The ideal choice for lower hedges.

Japanese barberry (Berberis thunbergii cv.) - A great choice for small to medium-sized hedges; dense and takes pruning very well. Ornamentally, it’s the best of the bunch; rich green, dark purple or gold summer foliage, brilliant fall colors, showy yellow flowers and red berries. It’s the ultimate physical barrier, too - no person or animal will challenge a barberry hedge more than once in their lifetime.

Hedge Cotoneaster (Cotoneaster lucidus) - It’s name says it all; this shrub was destined for use in hedges. The form can be a little shrubby without pruning, so it is best used for trimmed hedges. It has antastic fall colors, and it’s very hardy.

Winged Burning Bush (Euonymous alatus) - A fine choice for hedging, but not as commonly seen in northern gardens. Takes pruning well, so it makes a good trimmed formal hedge, but is also very shapely without pruning, especially if planted well apart. Provides spectacular fluorescent red fall color.

Cedar/Arborvitae (Thuja occidentalis cv.) - The ultimate evergreen hedge plant, particularly some of the tough cultivars like Techny and Nigra. It’s the hardiest evergreen that takes pruning well, and is ruggedly durable. Can be used for medium to tall hedges.

Preston lilacs are a fine replacement for privets in the North

Privet (Ligustrum spp.) - The most popular hedging plants in Europe for medium to large shaped hedges, because they take pruning so very well; available in both evergreen and deciduous varieties. Like boxwood, though, not reliably hardy other than zone 5, perhaps a couple of really tough zone 4 varieties, but that’s about all.

Lilac (Syringa spp.) - Where privets won’t grow, this close relative does the job admirably. In fact, it might be the most versatile medium to large-sized heding plant in the North. It takes pruning extremely well, but then don’t count on flowering; go for a natural hedge if you’re after the flowers. Dwarf Korean makes a dazzling medium-sized hedge, while Miss Kim and any of the Preston lilacs are fantastic screening plants. Hardy as heck, too!

Yew (Taxus spp.) - Another common hedge plant in Europe, yews take pruning extremely well, and are second in line to boxwoods when it comes to topiary. There are actually more cultivars of yew in everything from dwarf to supremely tall, but the upright ones make the best hedges. May only be hardy enough for hedge use in zone 5 and urban areas in zone 4.

	This low yew hedge creates a visual delineation of the property line

Viburnums (Viburnum spp.) - These are far underutilized when it comes to large natural screening plantings, and yet there are spectacular varieties hardy for every zone. Try nannyberry and American highbush cranberry in zones 2 and up, snowball viburnum and Mohican wayfaring tree in zone 3 and up, Sargent’s highbush cranberry and Emerald Triumph in zone 4 and up, and of course all the lovely doublefile viburnums in zone 5 and warmer. Don’t prune these, though, as they don’t handle it well, and besides, it destroys their primary attributes!

Northscaping's Landscape Plant Search

Now you know the basics of hedges, and some of the finer plants for hedging. There are many more, though, so be sure to search through the Landscape Plant Search for the many others - just set the Landscape Application to “Screening”, and be sure to enter other characteristics such as height and spread to narrow down the results.

In the next part of this two-part article we’ll get down to the meat of how to actually install your hedge, so don’t forget to bring your spade, and be prepared to get a little dirty!

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