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Perennial Garden Color
By Dr. William C. Welch, Landscape Horticulturist
Texas A&M University, College Station, Texas
Landscape Design Possibilities
erennials are versatile plants that offer a variety of creative uses in the garden. Perennials, you will find, offer an infinite number of exciting combinations. From tiny terrace gardens of inner city apartments, to extensive country estates, perennials can add color, form, and texture, often for many years and with a minimum of maintenance. A look at some landscape possibilities should help to stimulate ideas for specific applications.
The Perennial Border
We inherited from England the perennial border style as we know it today, and it is a version of the cottage gardens that evolved during the seventeenth and eighteenth centuries. The two greatest popularizers of this planting style were Gertrude Jekyll (1843-1932) and William Robinson (1838-1935), who proposed it as a rebellion against Victorian gardens, landscapes that Robinson once described as “the ugliest gardens ever made.”
Typically, the gardens of upper-class Victorians featured rigid, geometric masses of brightly colored annuals, all maintained at a uniform height like tufts in a carpet. This style was known as “bedding out,” and it had gained popularity after 1845 when the British government lifted the tax on glass. By lowering the cost of building greenhouses on residential estates, this measure made it possible to produce annuals economically and in quantity.
In the place of these monotonous floral carpets, Jekyll and Robinson beautifully articulated more natural combinations of plants, primarily perennials, both in the gardens they designed and through their writings. They extended the flower season from a few months in spring and summer to all year long by using bulbs, ornamental grasses, and old-fashioned plants and herbs collected from the simple gardens of the English cottagers. Earth and plant forms inspired the new concept of garden design, as the plants’ season, ecology, and arrangement in nature created the basis for the design revolution so clearly espoused by these two pioneers.
Jekyll was an accomplished painter until her eyesight began failing in her forties, at which point she began fully devoting her talents to the garden. Taking the earth as her canvas and plants as her palette, she went to work on what she considered the ultimate expression of garden art, the herbaceous border. Jekyll fashioned beautiful pictures by carefully selecting plants, and then arranging them in the long clumps of color she referred to as “drifts.”
Through her selection of plants, Jekyll also varied forms, heights, color, and textures within her borders. To be successful, she believed, the designer must intimately know the growing habits and requirements, as well as aesthetic qualities, of the plants.
Jekyll, Robinson, and their followers also recognized the great importance of the quality of light. Shadow was of equal importance to color, form, and texture in their gardens. An American landscape architect of that era, Beatrix Jones, said, “Shadow is a color and must be used as one!” The depth and dimension that a feeling for a balance between light and shade contributes are as essential to a well-designed garden as to a fine painting. Indeed, the difference in the quality of light is a fundamental reason that English gardens differ from our own. The relatively cool, moist climate of England is conducive to more intense flower colors than our generally bright, sunny conditions.
English herbaceous borders were usually limited in space by constructed walls or hedges. These walls or hedges not only physically limited the garden space, but also provided a sense of continuity or organization to the composition. Strong, simple organization contrasts with the wide variety of plants, each plant displaying colors, forms, and textures and reaching its peak at a different time of the year.
The design philosophies that Jekyll, Robinson, and others created and refined are as appropriate today as ever. The major challenge is for the designer to be sufficiently familiar with the palette of plants adapted to our area, so that the English herbaceous border can be successfully interpreted into our climate, topography, and life-style. This is no small task, but when done well, it is a splendid form of garden design. A final consideration to keep in mind is that to be at their best, herbaceous borders require considerable space. For small properties, the idea of a cottage garden may be more appropriate than a border. There are always exceptions, but minimum dimensions for borders should be in the range of 5 to 6 feet wide and 20 to 30 feet long. Wider and longer borders offer more opportunity for manipulation and gradation of color, form, and texture.
The Mixed Border. The mixed border is a combination of perennials, annuals, and flowering shrubs. The same design concepts that apply to the herbaceous border also apply to the mixed border, although it usually requires more space, since the effect is partially dependent upon shrubs such as old roses, as well as small flowering trees. Reseeding annuals can also be an important part of the mixed borders. As with herbaceous borders, having as little bare ground showing as possible is important. This not only results in a fuller and more satisfying appearance, but also provides less opportunity for weeds to grow and compete with the ornamental plants.
Old garden roses offer many possibilities for integration with perennials and annuals in this manner. Many old roses are large and handsome shrubs, but there are also many intermediate and smaller types that are well suited to modest sized properties.
Climbing roses and other flowering vines may also be trained on walls, trellises and arbors to provide a sense of vertical space, useful in developing gardens into a series of outdoor rooms. Gardens developed in this manner offer continually unfolding vistas that add to the viewers' interest by never allowing them to see the entire development at one time. This plan -- dividing the garden into a series of different rooms -- also allows for the design of smaller areas featuring specific color ranges, plant specialties, or other garden themes.
Annuals are a good way to quickly fill empty spaces and provide quick color in mixed borders. For the first year or two after planting, mixed borders may appear a bit sparse, since roses and other flowering shrubs require more time to develop than most annuals or perennials. During this interim, annuals can provide important fillers.
Cutting Gardens. There are several advantages to creating a cutting garden. Where we enjoy and use flowers in large volume in the home, their removal from borders and other landscaped areas may detract from the intended effect. By providing a special cut-flower garden, the gardener can anticipate and plan for these needs without disturbing or diminishing landscape plantings. The well-planned cutting garden also offers another very practical advantage: annuals and perennials may be conveniently and efficiently grown in rows where they can be easily gathered and maintained.
Cutting gardens need not be unattractive, but it is a sensible plan to locate them in an area where they are not a focal point when not at their peak. Old-time gardeners of Texas and the Gulf South often included cut flowers in the vegetable garden where they could tend and harvest them easily. Finer estates in our area would sometimes have a separate area devoted to producing the favorite cut flowers of the family. Annuals such as marigolds, zinnias, poppies, sweet peas, bells of Ireland, nasturtium, globe amaranth, and larkspur were frequently found in vegetable and cutting gardens of our ancestors. Shasta daisies, phlox, and chrysanthemums were especially popular perennials.
The Contemporary Cottage Garden
Today’s home owner can easily update the cottage gardening style so common in Texas and the Gulf South 50 to 150 years ago. A garden of this sort is particularly appropriate for townhouses and other small properties, where most modern landscaping efforts consist of a few uninteresting evergreen shrubs and ground covers unimaginatively placed against foundations of the structures. Traditional cottage gardens need not be extravagantly expensive, nor must they require great physical sacrifice. They are appropriate for new housing developments in the city, suburban bungalows, or country homes.
There are few rules to keep in mind when planning a cottage garden. Usually, they are modest in size, often enclosed by picket fencing, walls, or hedges, and contain a wide variety of plant materials favored by the owner because of their beauty, an emotional attachment, family preference, or real usefulness. Cottage gardens reflect one of the best aspects of America’s combined North European heritage -- individualism. Since they should reflect the tastes of their owners, no two cottage gardens should ever be alike. Gardeners should study the countryside and older gardens in their area. Native plants and those that have been successfully grown in local gardens for many years are often the best choices.
One writer felt it was impossible for the true cottage garden to be in poor shape, relying as it does on the natural form of the plants. Andrew Jackson Downing (1815-1902), the great American architect and probably our first professional landscape architect, thought that the cottage garden was “perfect of its kind,” and that the charm and attractiveness of these gardens made them “little gems of rural and picturesque beauty.”
In addition to enclosure within fences, walls, and hedges, extensive collections of plants, and limitations in size, cottage gardens usually had a straight walk or path leading to the front door. Another typical feature was the separately enclosed “swept” backyard. There was no turf or ground cover in that space, and where the ground was free of plants, the cottage gardener would periodically sweep the bare earth with a broom. They often planted backyards with small fruit trees, and included outbuildings, a chicken run, and chicken coop. Curving or straight walks of native stone or brick sometimes intersected the front walk near the entrance and provided access to the sides and back garden areas.
Sometimes cottage gardens included touches of formality, such as a parterre that might feature a sundial, birdbath, or other garden ornament, and garden benches.
Container Gardening. Container gardening is well rooted in history as a practical way to replace lost ground space in our urban environments. The effective selecting and placing of container plants can add formal or informal appeal to the garden. Advantages to container culture of perennials, roses, and annuals include the ability to control soil quality, watering, and placement of the plants. Most containers are relatively portable, and may be grouped or moved to take advantage of seasonal displays. Another advantage of container gardening is that tropical plants, such as Bougainvilleas, may be used in areas outside their natural range of cold tolerance by moving them to protected locations for short periods during the winter.
Perennial plants with cascading growth habits such as Asparagus sprengeri, lantana, verbena, and dianthus are particularly effective in containers where they can spill over the edges to create their special effects. Large-specimen trees and shrubs are often more attractive when the soil at their bases is covered with various flowering annuals or perennial plants. Flowering bulbs may also be included, to add their special effects at various seasons of the year.
Hanging containers can add still another dimension to the landscape. When used with restraint and scaled to the surroundings, hanging ferns, lantanas, and various cascading annuals and perennials can be significant additions to courtyards, entrance areas, and terraces.
Container plants usually require more maintenance, however, than those planted directly in the ground. Restricted root zones in containers require more frequent watering and fertilizing to keep plants in top condition. Plants in containers are also more susceptible to damage from extremes of cold or heat, since the roots are above ground and more exposed to the elements.
Both aesthetic and practical factors will dictate the choice of containers. Unglazed clay pots generally require more watering than plastic or glazed pots since water and air actually penetrate the relatively porous clay. A drainage hole in the bottom or side is essential for success in growing most plants in containers. If containers without drain holes must be used, consider “double potting” by simply lining the undrained container with a smaller pot equipped with drain holes. Since the growing area is restricted, it is important that the media be of high quality. Packaged potting mixes are available in large or small quantities, and are a practical choice for most situations. If soil is used, it should be mixed with liberal amounts of sphagnum peat, compost, or rotted pine bark.
Pockets of Color. Although we have focused on herbaceous borders and cottage gardens, there are other effective ways to use perennials in the landscape. Most landscapes have sufficient evergreen shrub materials to avoid a totally bleak look, but there is little seasonal change or flower color. For those who are interested in adding color to this type of planting with perennials, there are usually good opportunities.
By enlarging planting areas in front of evergreen shrubs, preparing modest-sized spaces for clumps of seasonal color is often possible. Make sure, however, to plant a sufficient quantity of the flower of your choice so that the effect is not just a “spot” in the overall picture. Keep in mind that shrubs and nearby trees may have so completely laced the potential planting area with their roots that sometimes they must be removed for flowering plants to be successful.
Possibilities that come to mind for this type of pocket-planting include masses or borders of some of the lower-growing daylilies or irises in front of evergreen shrubs. Entrance areas are a logical place to provide welcoming pockets of color. For most home owners, the amount of space in which they can comfortably maintain annuals or perennials is relatively small. Concentrating these plants where they will be seen and enjoyed the most seems sensible. Perennials generally require less maintenance than annuals, and since they often tend to return each year, they can be a wise gardening investment.
For pockets of color around outdoor living areas, swimming pools, and entrance courts, containers offer possibilities. Portability is a special asset of container plants, since they can usually be moved to a less prominent location when not at their best.
With our long growing season and relatively short winters, landscape maintenance becomes an almost year-round affair. By selecting well-adapted perennials and placing them in the most important place, year-round color can become a practical reality.
Woodland areas offer special challenges and opportunities for gardening. “Natural gardens,” Beatrix Jones wrote at the turn of the century, “are hardest to fit into residential gardens because they have no artificial straight lines or ornament for emphasis.”
If you plan to garden on a heavily wooded site, first consider removing some of the underbrush and low-lying limbs of trees. Often, it is sensible to remove small, weak trees that are too close together to develop or contribute to the overall effect.
In her book Wood and Garden, Gertrude Jekyll suggested tying white paper ribbon around the trunks of trees being considered for removal, then observe them for several days from various angles before removing. Removing trees is much easier than putting them back! Shade is a major challenge to successful woodland gardening. Sometimes climbing up and thinning mature trees will not only provide more penetration of light, but will also enhance the tree’s beauty by exposing its structure.
Improving the soil in woodland areas will also pose a problem, since woodland soil tends to be filled with roots. Although several inches of leaf mold and leaves may cover the surface of the ground, this layer rarely contains enough organic material in which to plant successfully. At least 5 to 6 inches of compost, rotted pine bark, peat moss, or similar material should be applied to the soil surface before spading or tilling it in. Slightly-raised, irregular paths of bark, mulch, or natural-colored gravel can add a nice touch to wooded gardens while providing pedestrian circulation and design continuity.
Since deciduous trees all allow considerable sunlight to reach the ground beneath them during winter and early spring, woodland gardeners tend to rely on spring flowering plants. There are, however, numerous ferns, aspidistra, Vinca major, liriope, and others that can add textural variation and green hues to such a setting. Native shrubs like black haw, dogwood, and Mexican plum also provide good fall color as well as spring bloom. Certain of the summer-flowering annuals, such as impatiens, wax begonias, and caladiums, are dependable sources of bright color in shady gardens.
Woodland gardens are more difficult to create than cottage gardens or herbaceous borders because they rarely have well-defined boundaries, and can easily fall into a stiff or unnatural appearance. Groupings of spring-flowering bulbs are popular in wooded areas or near their edge, because they will look natural, once established, especially if set out in “drifts” as suggested by Jekyll. Some experts even recommend pitching bulbs over one’s shoulder and planting them where they land to ensure a “natural” look!
Click on the butterfly for a "Partial List of Perennials for Texas Landscapes" by Dr. William C. Welch
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