Clippable Plants

This is an excerpt from the Book called “New Classic Gardens“ by Jill Billington . Continue reading to learn more about Clippable Plants, thanks to the author.

Clippable Plants

Strong lines and shapes can be made by adjusting a plant’s natural growth habit and formal gardens have always relied heavily on the clipped forms of evergreens such as box(Buxus sempervirens)and yew (Taxus baccata). Other accommodating evergreen shrubs, like myrtle (Myrtus communis) and cotton lavender (Santolina chamaecyparissus) are ideal for precision shaping because they have dense, small-foliaged growth that regenerates from the stems or branches. When sheared, the mass of tiny leaves makes it easy to achieve sharp edges. Even when the profile is blurred by new growth, the density of these shrubs ensures the maintenance of the form.

Hedges and parterres

Hedging can be the most influential element in a formal garden. The architectural nature of continuous runs of hedging may be used to emphasize a geometric layout, define routes and vistas, add boundaries and enclose spaces. Whether it is as tall as a two-storey house or as short as 15cm (6in), an evergreen hedge is constant in winter and a good backdrop in summer. Parterres traditionally made patterns in the garden. They developed from the idea of using low hedges to define and edge small beds, usually of geometric design, filled with low-growing herbs like thymes. As the fashion evolved, parterre designs became more elaborate, sometimes taking the shape of a fleur-de-lys or a swirl of paisley, and the spaces were filled with seasonal flowers or simply coloured gravels.

Hedges

Yew is the richest backcloth for any garden. It is dark and classy and will do as well in shade as in sunlight. It is renowned for its longevity and, because new leaves will grow even from very old tree trunks, it can always be relied upon to renew the form required. Where winter temperatures drop well below freezing, the European yew (Taxus baccata) will not do and should be replaced by taxus media ‘Brownii’ This has a slightly softer look, yet can be clipped with the same sharp accuracy. All yews will suffer in poorly drained soil, needing it to be moist but free-draining as well as acid to neutral. When well suited, Yews will grow as much as 30cm (12in) in a year; they should be clipped only once, in mid-to late summer. Yews are toxic so should not be planted adjacent to meadows because of the risk to domestic animals.

Other conifers, like thuja plicata ‘Atrovirens’, create dense, lighter green hedging with a softer look. And for the fastest grower in the west, Lawson’s cypress (Chamaecyparis lawsoniana) grows at a rate of 1m (3ft 3in) a year. Like all forest trees, these conifers should be clipped, early in their life, to approximately 30cm (12in) below the chosen height so that the softer growth will thicken before attaining full height the following year. After this an annual clipping regime is essential to maintain a dense hedge; avoid cutting into the old wood, however.

Large-leaved hedges like hornbeam (Carpinus betulus), elaeagnus laurel (prunus laurocerasus) and beech (Fagus sylvatica) may be used in the formal garden where they will give a softer profile than more tightly shaped plants. That can be clipped but look better when cut by hand with secateurs. Both deciduous hornbeam and lime (Tilia) maybe pleached, which involves training their side branches horizontally to create parallel lines, to develop a stilt hedge. In this procedure, all other growth is woven in or removed, forming a dense leafy screen for 1.5-2m (5ft-6ft 6in) above the row of tree trunks, 1.5m (5ft) in height, which allow low views through. Stilt hedges are best purchased pre-formed, with their parallel lateral branches already trained to a timber frame. A revival of old techniques includes the use of woven and clipped hazel and willow hedges in contemporary gardens; they can b ordered ready-trained.

Dwarf hedges and parterres

There are many different forms of common box (Buxus sempervirens) that will reach over 6m (20ft) high and wide if required. But the slower-growing dwarf version, B. sempervirens ‘suffruticosa’, which may grow to 1.2m (4ft), can support really meticulous clipping to maintain a medium or low edging hedge of 75 cm (2ft 6in) down to 30cm (12in). It is perfect for preserving the detail of parterres. There is a variegated form, B. sempervirens ‘Elegantissima’, with cream edging. The Japanese box (B. Microphylla) has tiny leaves and the form ‘Green Pillow’ makes squat hummocks which look stylish in a minimalist group or repeat planted.

Other hardy plants suited to low sheared hedging and therefore often used to build parterres include some with silver-grey foliage. Cotton lavender (Santolina), cultivar of scented lavender like lavandula angustifolia ‘Hidcote’ and the tender French lavender (L. Stoechas) will provide gentle grey dwarf hedges. Both the Clippable evergreens lonicera nitida and L.plieata have tiny green leaves. In warm, sunny climate, the aromatic but slightly tender myrtle can take over from box. It grows fast and can be clipped low or at 2.5m (8ft) if needed. Look for the subspecies tarentina, the most compact and windproof, which was a favourite in roman gardens and is still popular in Mediterranean regions today.

Topiary

Topiary is an ancient craft in which suitable evergreen plants area tightly clipped to shape to make freestanding sculptural forms. All the small-leaved evergreens referred to above, particularly box and yew, as well as hollies and the reliable but rather dull privet (Ligustrum) can be clipped into any chosen shape. Though hollies will lose their crap of berries when sculpted, the foliage has a coarse –textured look, emphasized when variegated, and this can enliven a topiary garden of yew and box. The sculptural possibilities of these plants have historically been explored as spirals, cones, pyramids and layered ‘cakestands’, as well as the whimsy of animals and grotesques. These have now largely given way to the minimalist geometry of cubes, cylinders, rectangles or art deco shapes.

Topiary work imparts a silent presence to the garden, instilling respect for the space and bringing the; visitor to a halt. In the past, it was used formally to mark entrances, flank paths and add year-round ornamental form, emphasizing a garden’s three-dimensional design by its static presence. Today topiary is still used for the same purposed but in a far less ornamental manner, while its abstract, creative impact has come to the fore. Those stationary sculptures are often placed so that they produce an asymmetric tension, emphasizing the space around them. And while geometric form like pyramids, cones and spires take the eye upwards, rounded forms squat together, making small mountainous hillocks.

Ancient topiary has often lost its original precision and new shapes have developed over the centuries, the living result a happy compromise between man and nature. These abstract shapes are neither symmetrical, geometric nor figurative but instead have become strangely deformed ‘mounds’ with a theatrical presence. The formality of oriental topiary is a little likes this; it is less mathematical and more organic, taking the plant’s growth habit into account. In the gardens of Japan, azaleas are often topiaries to make compact mounds. Their small, densely packed laves cope will with hard pruning so they can be shaped into almost any form but are usually clipped as rounded hillocks, crammed together like boulders or clouds. Azaleas tolerate being annually restrained so that they remain the same size, which is part of the reassuring tranquility of the garden. However, the seasons change their appearance and since azaleas flower it is best they are one colour: a patchwork would disrupt the calm.

An oriental influence can also be a softening one in modern classic gardens. ‘Cloud’ topiary is molded from the natural habit of a shrub by selecting wide-spreading branches to hold out small cumulus mounds of clipped foliage; all non-essential branches are removed. Box, holly (llex crenate), juniperus chinensis and pines like Japanese white pine (pinus parviflora), are suitable; a pretty Chinese privet (Ligustrum lucidum), often available as a small lollipop tree, can also be clipped as cloud topiary.

Practicalities when clipping topiary, assess right angles using a plumb-line, or make a wooden frame or template to use every year. ‘Formers’ can be purchased ready-made in wood or metal and these are retained within the finished work, rather like armatures. Yew needs clipping once a year and lonicera twice. Faster-growing shrubs like privet demand regular attention every two to three weeks. Hand shears will enable you to keep control of any freestanding shape, whereas electric shears are ideal for long runs of hedging and will maintain the precision of established large topiary. The sides of tall hedging should be battered towards the top, allowing light to reach the lower areas and snow to slide off the hedge. Some specialists will carry out bespoke topiary if you are not confident about doing it yourself; once shaped however, both hedges and topiary are simple to maintain.