Hedges

This is an excerpt from the Book called “The Art Of Creative Pruning” by Jake Hobson. Continue reading to learn more about Hedges, thanks to the author.

Three

Hedges

Hedges-like them or not, they play a crucial role in most gardens. However, rather than existing solely as the perimeter, backdrop, windbreak or screen to a garden, it is when the humble hedge is made into something more creative that it becomes a feature in its own right, on an equal footing with topiary, borders or lawns. If you will excuse the pun, it is time to think outside the box.

To start with, let’s look at what makes a good hedge. Deciduous or evergreen is the first question. In Europe and much of North America, deciduous hedges in the garden tend to be most commonly planted with beech (species of Fagus) or hornbeam (species of Carpinus), both of which hang onto their leaves during winter, or dense, thorny species such as Crataegus or various Prunus. The notion that deciduous hedges are less dense in winter is only partly true. Crataegus and others tend to get so dense after a while that they become an almost solid mass, even in the depths of winter, while the brown leaves of beech and hornbeam allow for the character of a semi-permeable hedge, which filters through valuable light on gloomy afternoons.

Evergreen hedges come in all shapes and sizes, depending on location (hardiness), trends (thankfully, it looks like we are coming to the end of the Leyland cypress trend at last) and purpose (speed of growth, eventual size, etc.) Yew and box are the heroes of hedges, X Cupressocyparis leylandii the villain, but nearly all evergreens also have something to offer.

The key to a god hedge is its batter-the angle of its sides. To allow enough light to the lower half of the hedge, it should be wider at the base than at the top. It is an exaggeration to say that without the right batter the hedge is doomed, but it will certainly struggle to remain healthy and dense from top to bottom. One rarely notices good batter, but top-heavy hedges with bad batter that balance precariously like upturned chunks of cheese and are inevitably bald at the bottom, stand out like a sore thumb.

Next up is the formative pruning of young hedges, to ensure that they are dense and bushy at the base to start with. The traditional approach is to cut back new or recently planted hedging plants, to prepare good foundations. Thinner, more straggly plants such as species of Crataegus, Prunus, Buxus and even Lonicera nitida all need pruning right from the start to encourage a good foundation. This means cutting back quite hard into the plant after planting, repeating this the next year. Other species, beech and hornbeam for example, should be cut back by up to one-third of the leader and side branches. Bushy conifers like yew, for example, need very little formative pruning.

In much of northern Europe, the practice is to plant much taller, thinner nursery stock than is common in Britain and to plant them far closer together. An example of this can be seen at Jacques Wirtz’s garden in Belgium, where tall, narrow hornbeam hedges create an elegant screen at the front of the house. I always enjoy coming across small differences like this between different cultures-books and education normally tend to toe the line, but something as common as hedging often becomes ingrained in our minds without much thought: plant small, cut back to make bushy. Yet across the Channel, in places closer to London than my own home, we see almost exactly the opposite, reminding me that there is still plenty of room left for the inquisitive gardener. In something as personal as one’s own garden, so many opportunities arise from keeping an open mind. I wonder what they do in Norway?

The Hedge As Architecture

So, rather than looking at how to grow a good hedge, which when it comes down to it, most people figure out for themselves without too much trouble, let’s look at how to make hedges more interesting-by using them as architecture and promoting them to a more assertive role in the garden. There are architectural features that are directly related to their stone and brick namesakes-buttresses, crenellations, windows, arches, niches, whole rooms even, but there are also pleached hedges, hedges on stilts, double and triple hedges, even mazes. Then there is design, and the use of the hedge not as a hedge at all, but as sculpture. And size. Very big, or wide hedges have a character all of their own. So whether your hedge is one of centuries-old yew, common privet, or even gloomy conifers, all sorts of things are possible.

Buttresses

When it comes to cathedrals, buttresses come in various shapes and sizes (remember flying buttresses?), but in the garden they are used not for structural reasons, but for visual impact. One normally comes across them in formal topiary gardens, appearing to prop up yew hedges. By breaking up the hedge, they make a series of bays that offer up all sorts of opportunities: if the hedge is at the back of a lawn, then benches and sculptures can fit snugly in the bays, framed by a buttress on either side. If it is at the back of a border, then the border can be planted up in themes; if in a kitchen garden, then vegetables can be planted in rotated beds.

They also make great places for games, and of course provide perfect firing positions and cover from imaginary enemy onslaughts. If, as has happened at Shakespeare’s New Place Museum in Stratford upon Avon, one neglects one’s buttresses and they turn from the imposing architectural things they were intended to be into great, swollen carbuncles, then they still serve similar purposes, with the added charm of a tumbledown country cottage, as if made of slowly decomposing hay bales rather than well-clipped yew.

Battlements And Crenellations

I imagine that most crenellated hedges are instigated by men, old men probably, for they are the logical progression from the sandcastles, camps and dens of childhood, for the young boy stuck inside the grown man. As with hedges in general, the character of the maker inevitably manifests itself in the results, so some crenellated hedges are tight and exact, while others are rather more shambolic, as if they have endured months of siege and heavy cannon fire.

The principles of crenellation construction are very simple. Once embarked on, it only takes a couple of years to turn some shaggy lumps at the top of the hedge into clearly defined fortifications. Ideally, the trunks of individual plants within the hedge should correspond with the merlons (the high bits) not the crenels (the low bits) as the growth of the trunks will be more vigorous-work with the hedge, not against it.

When it comes to clipping, unless you want your battlements to look like the Alamo, you need a bit of discipline to keep the tops of the merlons in line, the bottoms of the crenels flat, and the sides straight. Opting for the higgledy piggledy approach gives you more leeway for error, and the results can be just as effective.

Windows

Windows in hedges are great-something as simple as a hole can add humour, surprise, depth, symbolism and even poetry to a garden. Just as windows in walls let in light and frame views, so do hedge windows in walls let in light and frame views, so do hedge windows, but somehow, because it is not the sort of thing one normally sees in the garden, it injects an element of surprise too-and who can resist poking their head through a good hole in a hedge?

The best windows are not necessarily planned, but often materialize out of a patch of poorly growing hedge, suggesting themselves first as holes. They only become windows when properly framed, which is the tricky bit to do well, especially in wider hedges, where light has trouble reaching in. The basic principle is to cut part of the hedge’s foliage away with secateurs to reveal a rough window shape, taking care not to cut too much from the top of the hole, as the hedge will only regrow reluctantly from above. If need be, train down a thin branch to from the top frame. Start using shears or clippers to form dense frames, then clip as frequently as the rest of the hedge. Great fun could be had forming muntins from horizontal and vertical branches-and what is to stop them being glazed as well?

Arches

Nothing is more architectural in the garden than the arch. Used in the garden it takes the form of a gateway, an opening within a hedge. Extended into aqueducts, arches in the garden seem particularly popular in Germany-Schwetzingen Palace, for example, has a fine lime, or linden, aqueduct, echoing the real brick one that runs through the grounds. Essentially, this is a hedge with doors cut into it. It is flat along the top and each column is formed from one lime tree that is clipped close to the trunk for the vertical ascent, and allowed to connect on each side with the next tree. These arches seem as contrived as anything in the garden, even more so than much topiary, yet they fit in perfectly here, thanks to their architectural reference, their scale, and in the case of Schwetzingen Palace, their quality.

In Costa Rica, meanwhile, are the extraordinary arches at the church of San Rafael in Zarcero. Maintained, as it has been since its creation in 1964, by Evan-gelisto Blanco Brenes, this kind of garden is only possible with a single, no doubt wildly eccentric, creator at the helm. Fantastic avenues and double avenues of arches line the paths to the church. Not formal, regular arches such as you would see in Europe, but a writhing array of stalagmites that could only have materialized on the same continent as the magical realism of Gabriel Garcia Marquez.

To recreate the wonderful shapes at Zarcero is surprisingly easy. They are formed out of two plants, planted as if part of an avenue (in fact, in this case I suspect that they did start life as a regular avenue). At the appropriate height, simply train the leaders in towards each other, bending down with wire or string and tie in with a cane. New growth from the trained beams is then clipped into shape, much like any topiary or hedge. Similar effects are seen all over the world in different guises: rose arches in cottage gardens spring to mind, as does yew in English churchyards. Indeed, it is interesting to compare the churchyard at Zarcero with the one at St Mary’s Church Painswick in Gloucestershire, England. Most churchyards in the UK have a yew tree or two in their grounds, either free-growing or clipped, but St Mary’s is no ordinary churchyard-there are hundreds of them here, pruned into individual standards and arches. Their form is less extraordinary than their Latin counterparts, more Laurie Lee than Garcia Marquez perhaps, but equally evocative of their environment.

In the case of San Rafael, the hedges there are a Cupressus species, most probably Cupressus lusitanica. While species of Cupressus respond well to regular light clipping in general, ultimately they are not ideal for topiary projects because, like many other conifer species, they resent being cut too hard. Clipping the new growth is fine, but cut back into the woody growth and they start to object, hence some of the arches at San Rafael having bald patches, particularly near the bottom of each plant, where the branching is older.

The Japanese have their own take on the arch, as they do with most things. Outside their homes it is common to train a side branch of a tree over the gateway, framing the approach. This can also be over the driveway, and often the branch extends further still, continuing beyond the gateway around the perimeter of the garden. The Japanese black pine (Pinus thunbergii) and the yew-like Podocarpus macrophyllus are popular material for this treatment, known as monkaburi in Japanese. Despite the unusual look, it really is only an extension of the standard training and pruning that they use for their niwaki (garden trees), and is also remarkably similar to fruit training techniques.

There comes a point with an arch where, if it gets too deep, it ceases being an arch where, if it gets too deep, it ceases being an arch and becomes a tunnel. Quite where that point lies is a good question, but it is obvious enough when it happens. Tunnels of solid hedge, especially those of evergreens and conifers, are difficult to grow because of the lack of light within the tunnel, but deciduous trees do much better when trained and pruned into shape. The same can be said for houses, igloos, and yurt-shaped domes, where horn-beam or beech are the material of choice (or ash in the case of the artist David Nash’s dome).

Mazes

Unless one is seriously into topology, the scale of real mazes is beyond the reach of the average garden. Their attraction lies in the fun they bring, and the visual effect they create, especially when seen from above. The sculptural interplay of horizontal and vertical planes, whether flat-topped and formal or rounded and organic, brings a new dimension into the garden, especially in the right light-usually early morning or late afternoon, when the sun is low. From a sculptural point of view mazes are pretty similar to complicated parterres, although of course their function, and height, are rather different.

The azalea maze at the Getty museum in Los Angles, designed by artist Robert Irwin, is a great example of form over function and visually is one of the more interesting cases I have come across. Described as a floating maze, it is planted within a shallow pool and gives the impression of being inflated, like an elaborate lilo, or inflatable mattress. Surrounded by water, it cannot actually be walked through, so whether it qualifies as a maze at all is open to discussion.

Planted with evergreen Kurume azaleas (Rhododendron species), it has more than a hint of Japanese influence to it-in fact, there is a strong Japanese influence to much of the pruning in California, where many Japanese have lived since the early twentieth century. The low, rounded forms are suggestive of Japanese Karikomi pruning and tea plantations. Being azaleas they flower (mostly pink, with some white) in late spring. Cleverly, the dead ends are blocked with pillows of azalea, adding more tension and energy to the design than had they been solid masses joined to the sidewalls.

This maze is striking partly because of its unusual form (the low, sausage shapes) and being set in water, but also, crucially, because of the angle the public view it from-it was designed as part of the garden as a whole and all around it are raised banks so one always looks down on it from above rather than at it, along the same horizontal plane. It is quite definitely designed to be looked at rather than explored, as an artwork rather than maze, which might take the fun out of it, but this is what creates its marvelous sculptural presence.

Doubles And Trebles

Hedges can also add a sculptural element to gardens through repetition. Double or triple hedges, either with varying heights or terraced down a slope, provide a strong interplay of horizontals and outlines, offering some of the visual excitement of the maze but on a less imposing scale. A simple laurel hedge (Prunus laurocerasus) I pass most days has three layers to it, sloping down to the road on what would ordinarily be a plain grass bank. The space between the hedges not only creates a sense of depth, but also provides useful access for clipping. It adds a feel of the exotic to a pretty dreary stretch of the road approaching Yeovil-the laurel itself could not be more suburban, but to me the stepped effect evokes tea plantations high in the hills, somewhere in the Far East.

The same effect is used in the Raikyu-ji temple in Okayama, Japan, where the clipped azalea karikomi, modeled on wave patterns, flows along the slope at the back of the garden. In sunlight, the fissures in the hedges are cast into deep shade, providing a strong contrast with the bright green leaves of the surface. The patterns of light and dark and the sheer, vertical cliff faces that are cut into the sloping bank create a much more abstract feel than the karikomi gardens at places such as Shisendo-in, as this appears to be much more like a three-dimensional, computer generated landscape rather than plant life. Again, this artificial landscape seems related to tea plantations, at the point where horticulture meets agriculture.