Seasonal Planting

CHAPTER 2

DESIGN PRINCIPLES AND CHANGE

Successional planting involves layering plants in a design with the aim of extending the flowering season, providing year-round interest, and creating moments of drama through change. The beauty of a garden is partly found in its impermanence, ephemerality and surprise, and at times of regrowth. We do not want to lose these signs of change by creating static gardens full of clipped evergreens and the techniques in this book always try to bear this in mind.

In later chapters, we will explore how different design techniques and planting palettes can provide seasonal interest. However, it is important not to forget the fundamental principles of good design, and here we examine how these can be used to embrace change through the seasons and the years. These are divided into two: general principles that apply to the design of the garden as a whole, and the principles that are associated with details such as flower and leaf shape. The chapter ends with a discussion about the unique challenges of designing small gardens and considers how these spaces can also be a source of unexpected delights throughout the year.

Embracing Change - the Fundamentals

Garden and landscape design is about sculpting space; it is fundamentally a three-dimensional challenge underpinned by time. This means that the design is never finished, is always changing, there is never a point at which you can say, 'That's it, this is the garden completed exactly as I imagined it.' Some changes are predictable and cyclical, but others are unforeseen, depending on weather conditions, soils, competition, maintenance and so on. However, good design ensures that gardens can evolve with these changes and still retain their structure, drama, functionality and atmosphere.

When embracing change, it is important that the designer works with the garden owner, setting expectations and discussing the development and management of the garden from the outset. Designers should have sustainability at the forefront of their minds, and this can go hand in hand with a discussion about how the garden will evolve through the years.

Balance and Scale, Mass and Void

When considering balance in garden design the first elements to examine are the masses and the voids. Planting and built structures create the masses and open areas such as water, lawns, paths and patios are the voids; the balance, and also the tension, between these elements contributes to the atmosphere of a garden. A harmonious balance is easiest to achieve with a symmetrical design, but it is more interesting to experiment with the asymmetrical interplay of structural elements. Slopes, different heights and changes in level all affect the balance of the design, as does the density and visual strength of the masses and voids. It is useful to remember that 'the garden is a maze in which people occupy the voids and the wildlife broadly speaking inhabits the masses' (Heatherington and Johnson, 2022: p.44) and I will look at wildlife in relation to seasonal change in Chapter 7.

Balancing elements in a design also requires an understanding of scale: the size of things relative to the surrounding landscape and human visitors to the garden. When designing the planting, it is important to think about the mood that it will create. If the scale is overpowering - if the masses predominate and tower over you - then the garden can feel claustrophobic and enclosed. In contrast, if the planting is sparse and low to the ground in a large open space, you may feel exposed and vulnerable. These uneasy atmospheres can play a part in a dynamic, interesting design but it is important to understand how plants can create these effects.

When designing the planting we are balancing the relative size, density and position of the plant masses. However, seasonal and annual changes may subvert the designer's intentions. Trees and shrubs may only achieve their full potential as masses after several years, and a group of tall perennials can form a colourful block in the height of summer only to be transformed into a void when cut back in the winter. This is especially evident in the case of a meadow. Nevertheless, these changes can be embraced if consideration is given to other elements such as the changes in light and shadow, mood, energy and atmosphere.

Dense planting and a clipped yew hedge form the masses in this garden, designed by the author. These are balanced by the voids of the contemporary pond and the tiny lawn, glimpsed beyond the hedge.

Atmosphere is influenced by the density of the plants, as well as their colour and texture, and change through the year adds excitement. A perennial bed with a combination of a tall Miscanthus and Veronicastrum virginicum, lower growing Astrantia, Epimedium and Allium 'Purple Sensation' will spring to life in early spring with the delicate low flowers of the Epimedium on their wiry stems. At this point the bed is little more than a void with potential. The new bronze growth of the Epimedium quickly creates a low mass of cover around which the coarser textured Allium and Astrantia leaves start to appear. In late spring and early summer, the mass becomes denser and more dominant, while the Allium flower heads rise above in dramatic purple accents. It is then the turn of the Veronicastrum and eventually the Miscanthus to dominate: the mass is now dense, rising nearly to eye height. In the autumn, this density gradually declines and the seedheads have a semi-transparent ephemeral quality, colours become more muted, leaves die, but this amorphous mass persists well into the winter before being cut back in February - temporarily a void again.

For the garden visitor, in summer this little combination can contribute to an atmosphere of enclosure and seclusion, whilst in winter the more open aspect may allow attention to be drawn to other views in the garden or beyond the boundaries.

Unity, Rhythm and Repetition

Unifying concepts and elements make a design more comprehensible and can also help to embed a garden into the landscape and create relationships with the surrounding buildings. Unity is expressed through the style of the garden, the concepts behind the design and the detailing. It may also be imposed by the site itself: the local materials, the surroundings or the genus loci. The style of a planting scheme may be formal, informal, naturalistic, tropical or minimal and concepts may include such ideas as gardening for wildlife, a jungle garden or an impressionist garden. The style and concept dictate the choice and combination of plants - the details of the design. When thinking about seasonal succession, some styles are easier to achieve than others. A formal garden relies on clipped evergreens, which will add structure throughout the year and the addition of perennials to bring seasonal change may disturb the clean lines, especially in the winter as they are drooping and dying. Similarly, a minimal design leaves little room for the diversity of planting that is necessary to create a truly successional scheme. At the opposite end of the spectrum, an informal or naturalistic planting design incorporates a wide range of perennials and grasses, but in order to unify the design these need to be contrasted with repeated static forms of judiciously placed shrubs and trees to add mass through the seasons.

The colours of the brick paver path echo those of the alliums and sedums, and the repetition of the silver Eryngium brings a unity to this planting design by Tom Stuart-Smith.

These unifying shrubs do not need to be evergreen. Beneath the tall oak trees of Beth Chatto's woodland garden, perennials and bulbs intermingle with abandonment in a random naturalistic fashion to resemble woodlands we might see in nature. However, she has also introduced shrubs into this tapestry, such as Deutzia, Buxus and Enkianthus campanulatus and the repetition of these forms brings a unity and a focus to the exuberance of the informal planting scheme.

The quirky shapes of the yew form a repeated refrain running through an intermingling carpet of green at Le Jardin d'Agapanthe, Normandy, designed by Alexandre Thomas.

In Beth Chatto's woodland garden, the white flowers of the Deutzia shine in the dappled sunlight.

Creating attractive successional planting schemes is easier when selecting a wide range of species. It might seem that diversity and unity are contradictory concepts, however, there are ways in which a designer can still unify rather than clutter the garden. Simplicity is often cited as a way of unifying a design, but it is not necessary to keep things simple. In fact, when thinking about designing for sustainability and for wildlife diversity, intricacy and complexity are more important (Heatherington and Johnson, 2022). Instead of focusing on simplicity, think about how plants are grouped together, the ways in which they form masses to contrast with the voids. Placing smaller plants in repeating blocks and drifts unifies the design and gives a sense of rhythm to the planting scheme. Within these drifts ephemeral species can be specified, adding dots of colour at certain times of the year or creating a gauzy, transparent overlay to the planting.

Repetition creates a rhythm to the design and introduces a dynamic element that leads the eye around the space. Consider the different forms, colours, habits, textures and scales of the individual plants and the plant combinations....