英国园林建设主意

The garden has been considered an essential element of a happy and full life since the beginning of time. As a result, landscape design has enjoyed equal stature with the major arts. Th e garden or landscape designer has held prominent positions in many cultures, including the courts of ancient Egypt, Renaissance Italy, Imperial France, China, and Japan. Master designers have generated many of the techniques of design through their own artistic talent, experience, and interpretation, as well as through strong sensitivity to the client, qualities of the site, and plants and materials used. Today, landscape design is popular with the average homeowner. However, moving high-garden type art to the backyard context is diffi cult. When using plants in landscape design, the result is usually oversimplifi ed and misinterpreted. Easy-to-follow “cookbook” landscape rules can be found in many popular landscape design magazines. Unfortunately, these publications do not discuss the overall three-dimensional structure of the design. Instead, they discuss the use of plants in terms of individual ornamental characteristics including form, color, and texture. In this type of approach to planting design, the most immediate visual attractions within the landscape are emphasized. One of the more important, basic, and classic aspects—the cre- ation of three-dimensional outdoor space with plant walls, fl oors, and ceilings—is overlooked. Th at is unfortunate since this aspect of planting design can evoke the longest- lasting overall impression within the outdoor experience. Th is publication outlines the oft en-overlooked concept of landscape design with plants as architectural, engineer- ing, and aesthetic tools that build an enjoyable outdoor environment. It is not intended to present any textbook rules for home landscaping nor discuss the most appropri- ate use of specifi c plant species. Such techniques of design are developed through one’s own design experience or through viewing the design of others. HO-62 Landscape Design with Plants: Creating Outdoor Rooms Janice A. Cervelli, former Professor, Landscape Architecture Plants as Architecture Plants with respect to architecture can perform two roles. Th ey can complement and reinforce the existing architecture of the house or structure, and they can create outdoor rooms. Trees, shrubs, and ground covers can be used to em- phasize the desirable architectural lines and masses of the house. Th e form and branching pattern of particular trees and shrubs can echo the vertical, horizontal, and diagonal roof and wall lines of a house. A pleasing, unifi ed, and harmonious appearance can result (Figure 1). Figure 1. Plants soften and fi lter light as well as blend with natural material. 2 Plants can be used to soft en and balance harsh and awkward architectural angles, masses, and materials (Fig- ure 2). Before actually purchasing and installing plants, an owner can plan the locations by assessing the desirable and undesirable qualities of the house. To do this, take a photograph of the front and back of your house, and sketch where plants are needed. Judge ultimate plant sizes at this time to ensure harmony with the house. You can use plants to frame desirable views of your house. Remember, the best views are not always from straight on. Oft en, views to the entrance or windows are more interesting from an angle as one approaches from a drive or walkway (Figure 3). Selective framing allows the viewer to see only the best parts of the house and yard in a sequence that builds up curiosity. Figure 2. Plant and house forms are in harmony. Figure 3. A grove of river birch is used to screen this house from the road. A sweeping drive, brought in from the left, focuses on the entrance of the house and discloses the rest of the house in a sequence. Views of the house are important, but views from inside the house onto the front or backyard are even more so, and they merit consideration. A large shrub or medium-sized deciduous tree with lacy foliage and branching pattern can be used to provide enframement, a sense of scale, and an interesting foreground to the viewer from inside. In the winter, the branching pattern creates the same eff ect. Such a treatment can double your enjoyment of the landscape. Be careful to size and space the plant so that it does not overgrow and block windows. Th e human eye has a tendency to follow the outline of the objects in the landscape. With this idea in mind, you can aff ect the apparent size of your house. By placing plants in increasing height away from the house corners, the horizontal lines are emphasized and its apparent length increases (Figure 4). Th is is especially helpful with boxy, two-story structures. 3 Th e same arrangement in a scaled-down version can emphasize and lead the eye to the entrance or large picture window. Placing large, conical evergreen plantings on either side of the entrance oft en has the disastrous opposite eff ect of emphasizing the vertical lines, making the house appear taller and narrower and creating an uninviting, inhibiting appearance (Figure 5). Th e proper placement of foundation plantings raises similar concerns. Evergreen foundation plants originally became popular for masking exposed foundation walls that were two to three feet thick and made of concrete block. Most foundations on newer homes rarely expose more than 12 inches and can be masked with a ground cover. Older homes oft en have attractive stone foundations that should be emphasized, not masked. It is not always neces- sary to place great amounts of expensive evergreen plant- ings around the entire house. It also is unnecessary to restrict the type of plant to evergreens such as yews or boxwood. Deciduous trees and shrubs are equally eff ective in complementing architecture. Deciduous plants can unify the architecture through a Figure 4. By graduating plant sizes away from the house, the apparent size of boxy, two-story structures is increased. Figure 5. Tall evergreens create an uninviting, inhibiting appearance to this entrance. branching pattern. For example, horizontal house lines can be unifi ed with a horizontal branching pattern. Deciduous plants also add an infi nite variety of color and textural interest throughout the year. All of this is possible without distracting from the main feature, the house. Th e growth habits and requirements of plants must be considered when they are used close to the house. When sizing a plant, take into consideration its mature height and width. Otherwise, an overgrown and crowded appear- ance that dwarfs and hides the house can result (Figure 6). Consult a number of information sources concerning plant growth. Check any special cultural and maintenance requirements of the plants such as soil type, moisture, sun exposure, and pesticides. Figure 6. Plants that reach large sizes at maturity are often planted too closely to the house when small. When mature, they dominate and make the house look smaller. 4 Creating Outdoor Rooms Th e word architecture suggests the creation of spaces or rooms for use by people. Inside the home, fl oors, walls, and ceilings are used to create diff erent settings for a variety of activities ranging from gardening, handiwork, and cooking to formal entertaining, relaxation, and active sports. As a result, greenhouses, garages, utility rooms, kitchens, living rooms, dens, studios, and gyms are created. Th e development of outdoor architecture or outdoor rooms utilizes the same elements as indoor architec- ture—fl oors, walls, and ceilings. Th e diff erence is that the elements of outdoor rooms are composed of plant materi- als that have a changing and dynamic, living quality. As time passes, the room will grow and mature and provide a varying seasonal display each year. Th e second role of plants with respect to architecture is the creation of outdoor rooms. Before creating such rooms, determine what number, type, and size of spaces are needed. List what type of outdoor activities you expect to conduct. Th e list might include entertaining, cooking, gardening, reading, painting, sunning, or relaxing. You might also want space for children’s play, active sports, stor- age, building projects, hobbies, and maintenance. Th ose activities that require a separate room must be noted, as well as those compatible activities that can be combined in one space, such as a workspace, storage, and parking area. Note the desired qualities of the space; that is, sun or shade, or hard or soft surfacing. Th e creation of the various outdoor spaces can take one of two approaches. Th e most typical involves the new homeowner in landscaping a house that had previously received some landscaping and where outdoor spaces such as patios already exist. Th e approach is similar to that of redecorating an older home: the basic fl oor plan remains the same while the qualities of the fl oors, walls, and ceil- ings are changed with the addition of a new rug, wallpaper, paint, and furniture. In landscaping, the designer should assess the condition of existing plants and views and determine what is to stay and what needs improvement. Th e result may be a simple cleaning-out, trimming, replanting of existing plantings, or planting of new foundation plantings. Th is approach may appear to be the most effi cient. However, it fails to completely consider the new owner’s special needs. Th e construction of most new homes is also completed with little consideration of outdoor rooms. Th e front and rear yards are left as two large spaces with the side yards as small voids (Figure 7). Foundation plantings around the house, hedges along the property lines, and a few shade trees are oft en added by the fi rst owners, but these addi- tions will do little to encourage the most effi cient spatial development in each yard. Figure 7. A small side yard developed into an intimate strolling garden. Th e second approach to room creation is the develop- ment of new outdoor rooms. Compare this to changing the actual fl oor plan of an old house by knocking out walls or building an entirely new structure. To develop a new room, assess the qualities of the existing site. Such qualities as views, topography, drainage, sun and wind exposure, and proximity to the house can suggest appropriate locations for activities. Th is type of assessment requires you as the designer to experience the site and characteristics on a frequent basis through all of the seasons. Th is activity will allow you to get a “feel” for the site and better match its qualities to your needs. Th e simplest approach to locating new rooms is to begin by extending the house’s interior rooms to the exterior. Th e outdoor room will take on a function and quality similar to the indoor room, producing a stronger relationship and harmony between the house and the landscape as well as increasing the apparent size of both. In this regard, the location of the house on the property and the fl oor plan of the house can help with strategic window and door loca- tions overlooking good views. Th e small patios and decks added to new homes by developers are a positive step in this direction. Similarly, the entrance foyer or vestibule can be extended outward by expanding and developing 5 the front porch and area. Garage and driveway access can be extended to include an outdoor work and storage space. Defi ne these rooms with plant or constructed walls, fl oors, and ceilings to avoid blending them into one large, characterless space. Further development of each individual outdoor room should begin by determining whether the space is inwardly or outwardly oriented (Figure 8). Inwardly oriented space is characterized by either complete or nearly complete enclosure and a strong central focal point. Certain areas for sitting, sculpture displays, patios, and hot tubs require enclosure for purposes of privacy, quiet, and concentra- tion. Rooms within rear yards will typically contain such activities and require this type of orientation. Outwardly oriented rooms are enhanced by amenities outside the space such as good views and breezes. Certain spaces may require selective cutting of existing plants to provide good views or the installment of new plants to Figure 8 (top). Inwardly focused space. Figure 8 (bottom). Outwardly focused space. frame the views. In most situations, activities taking place within the front yard are more public in nature and will require free visual access on and off the site and little en- closure; thus, it is outwardly oriented. Once you have determined the orientation and function of the outdoor room, you can defi ne the basic elements of architecture: fl oors, walls, and ceilings. Th e fl oor of an outdoor room can provide for continuity and a comfortable transition throughout a number of spaces. Th e fl oor can be created with pavement, lawn, ground cover, annuals and perennials, or low (1’ to 3’) shrubs. As in any building, the activity to take place in a room will determine the size and material of the fl oor. Just as work and exercise areas or kitchen areas have a durable linoleum, tile, or wood fl oor, similar outdoor areas in the yard should be underlain by a durable lawn or even hard pavement. Likewise, as a formal living room or entertainment area calls for a more decorative, plush carpet, so should a formal outdoor garden, patio, or terrace. A variety of swathes and ribbons of ground covers, annuals, and perennials provide the highly decorative eff ects of an oriental rug if carefully planned to take full advantage of seasonal interest. Th e type of plant materials used to defi ne the outdoor room also will suggest the function. Lawn areas typically invite low volume, pedestrian traffi c, and relaxation, while spots with ground covers, annuals and perennials, and low shrubs do not. You can create an activity-oriented room using a lawn area bordered by ground cover or low plant- ing beds. Or a passive viewing garden can be created with more elaborate planting combinations and little or no lawn (Figure 9). Figure 9. An outside extension of the entrance foyer creates a viewing courtyard of elaborate plant combinations instead of lawn. 6 In the same manner, suggest traffi c volume and direction with the creation of pathways using lawn and planting beds. Th ese pathways can act as a kind of breezeway to link two diff erent outdoor rooms (Figure 10). Th e extension of low planting beds to taller shrubs and tree masses and hedges can create very eff ective walls with which to enclose an outdoor room and direct traffi c to it. Choosing the type of plant to use as a wall is similar to choosing a wallpaper for its texture, color, and ease of maintenance. Th e leaf, fl ower, and winter branching pat- terns of individual plants provide the same visual qualities as wallpaper. Height and thickness or density of the wall are determined by inward or outward orientation of the space and required degree of enclosure. Low to small shrubs (2’ to 5’) can be used to suggest partial enclosure but still al- low views out of the space. Taller, dense evergreen shrubs (5’ or taller) in combination with smaller shrubs and trees provide the strongest enclosure. Tall and medium trees (25’ or taller) provide overhead enclosure but also allow views from underneath the canopy (Figure 11). Plants with more open growth habits can provide a partial screen to fi lter views. Outdoor walks also can be used eff ectively to screen negative views, sounds, and smells near the space (Figure 12). Th e size and intensity of these negative elements will determine the size, spacing, and density of the screen. Poor views will generally require dense evergreen plantings or constructed screens for year-round eff ectiveness. Un- pleasant smells require a combination of aromatic ground covers, annuals, perennials, shrubs, and trees to be placed downwind between the source and the property owner. An- noying sounds are especially diffi cult to screen with plants on small sites and require a combination of constructed walls, fences, and landforms. Plant combinations can act as fl oors. Walls can frame the views in both inwardly and outwardly oriented space. Use low shrubs and ground covers as a foundation to off set a central focal point such as a sculpture piece or patio in an inwardly oriented space (Figure 13). Taller shrubs and trees enclose a space and lead the eye to a central focal point. Framing an outward view involves the same concept but uses trees, ground covers, or planting beds to draw the eye out of the space (Figure 14). Outdoor ceilings are the most important part of the room, and you can create them with tall shrubs (10’ or taller) and small, medium, and large trees (15’ or taller). Th e orientation and scale or size of the room will determine the type of ceiling. Inwardly oriented space should have a wide variety of ceiling heights, density, and texture. Let desired intimacy or the scale determine the ceiling height. Figure 10. Planting beds and walks act as a breezeway between driveway and entrance courtyard. Figure 11. Various plant types, heights, and combinations create walls, partial screens, and overhead canopies. Figure 12. A sculptured hedge creates a partial screen between parking area and entrance courtyard. 7 Rooms intending a grandiose eff ect such as a dining room or ballroom require high ceilings. Victorian homes with 10- to 12-foot high ceilings bring a distinctively diff erent perceptual eff ect than the 8-foot high ceilings in more contemporary homes. With this in mind, you can create your style of outdoor room. Th e density of the tree canopy and the overlap will de- termine the amount of light in the room. Th e darker the room, the heavier and smaller it may appear. It may also render a cooler, more mysterious eff ect on the viewer. A brighter room is generally perceived as lighter, airier, more comfortable, and larger to the viewer. Fine-textured plants such as honeylocust render a lighter, airier enclosure. Tall, dense evergreen shrubs and trees such as yews, pines, and fi rs render a darker wall and canopy enclosure. Careful Figure 13. Low planting beds and overhead canopy enclose and complete this outdoor sitting area. Figure 14. An overhead tree canopy helps to frame the outward view from this wood deck. planning of the interplay between sun and shade at diff er- ent times of the day can also bring about dramatic eff ects of light and dark. Th e texture of the leaf and branching patterns across the sky in both summer and winter months also adds to the decoration of the room. Th e basic function, location, and orientation of the outdoor room can be further refi ned by determining the main motif or theme of the space. The Composition of the Outdoor Room We have looked at how plants can be used to enhance and frame a house or property and how to create outdoor space or rooms with plants as architectural elements. Th e next step is to give a pleasing form to the composition through the use of classic design principles such as unity, balance, and rhythm. Th ese basic design principles are common to all art works. Th ese qualities make artistic cre- ations continually beautiful, interesting, and meaningful. Plants as well as man-made structures can be combined in an infi nite variety to bring about balance, unity, and rhythm. What is meant by balance, unity, and rhythm? In a bal- anced composition, the elements of design are distributed in some organized arrangement or order. Symmetrical and a