|Plant Lighting:||Full Sun, Partial Sun/Shade|
|Season Color:||Late Spring to Early Summer, Fall|
|Max Height (feet):||29-40"|
Skilled designers combine plants and "hardscape" (stone, fencing, lighting and decorations), to create a beautiful garden.
Experienced gardeners have no problem deciding when to plant their peas, how deep to put their tulip bulbs, or how much to water their geraniums. But when it comes to garden design, even the most seasoned gardeners begin to sweat. We can spend weeks trying to find the perfect spot for a new shrub; spend an entire winter sketching plans for a new perennial garden; and agonize for years about how to reconfigure the front walk. Why do we find these decisions so paralyzing?
One reason may be that garden design is perceived as the work of experts: landscape architects, landscape designers, garden designers, and landscape contractors. Yet some of the most beautiful gardens in the world were not designed by experts. Sissinghurst, the home and gardens of Vita Sackville-West and Harold Nicolson, is a perfect example. So, too, are the gardens of Tasha Tudor and Thomas Jefferson. These gardens are the result of an attentive eye, a sensitive hand, and many years of experimentation—skills that are not the exclusive property of design professionals. Our goal in this article is to help you overcome the garden design jitters, and give you the confidence to finally remove that hedge of overgrown yews, install a flagstone path, or decide where to put a water garden.
Some gardeners wouldn't dream of planting anything without having a comprehensive design and planting plan for their entire yard. Others don't think about "designing" their gardens until several years down the road. And still other gardeners never develop a long-range or a short-range plan. They do their planning in the moment, poised with a shovel and a couple of homeless plants.
Which approach is right for you? It depends entirely on who you are and what you are comfortable with. If you have the confidence to forge ahead and follow your intuition, do so! If you feel the need to get some professional advice, then that's the best alternative for you. Both approaches are equally valid.
It is good to remember that there is no ultimate garden design for your property. There are as many different designs as there are gardeners. And even if you had a detailed plan that you executed perfectly, tomorrow would bring a new interest, a new challenge, and a whole new set of design decisions. The trees will mature and turn your sunny meadow into a shady glade. The weeping cherry that anchored your spring bulb garden will die and need to be replaced. You will tire of the cottage garden and develop a passion for dwarf conifers. In garden design there are no "right" decisions. What you have is a delightful (though sometimes unnerving) opportunity to express yourself. The hardest part may be trusting your own intuition, and allowing yourself to experiment as you evolve your own unique garden design.
One of the most valuable design tools is a site plan, or bird's-eye view of your yard. Seeing your garden on paper makes it much easier to identify underlying design elements such as traffic patterns, scale, and symmetry. A professional designer will give you a site plan that is precisely drawn to scale, but your own rough sketch or a survey map will be adequate for all but the most complex landscape designs. Once you have a plan to work from, you can start to indicate the positive and negative features of your yard (trees, shrubs, fences, outbuildings, pathways, views) and natural environmental factors such as light conditions and soil or drainage problems. Pathways and garden areas can be sketched right on the plan. If you enlarge sections of the plan, you can also use it to create your planting map.
Should you hire a professional landscaper or garden designer to help you with your site plan? If you have the means and desire to do so, it will probably be money well spent. Professional advice will always give you a valuable new perspective on your yard and gardens. You may follow their recommendations to the letter, or select only the elements that you find most appealing or most manageable. It is not necessary to contract for a full-scale site plan. Most designers will be very willing to focus their attention on a particular area (like the entryway). One well-conceived and well-executed feature may go a long way toward identifying a design style that you can then carry forward yourself.
What follows is a list of design principles that are common to all the creative arts, whether it be painting, music, literature, or garden design. Don't let them intimidate you. Just use them as tools to help you see.
Style. Every garden has a style or personality to it. Unless you have a very large yard that is divided into distinct areas or "rooms," it can be difficult to gracefully accommodate lots of different garden styles in one garden. Begin by thinking about whether you want your garden to have a formal or informal look. Consider your site, the style of your home, and your own personality. Though you don't have to be too rigorous about striving for a consistent style, you'll want to avoid a jumble of diverse and unrelated elements.
Flow. A garden is more pleasing if there is a logical progression from one area to the next. Think about how you would like someone to view and move through your garden. Paths are one way to connect some of the various parts to achieve a sense of order and cohesiveness. Focal points, such as a piece of sculpture, a distinctive tree, or a captivating view, can be used to draw the eye and pull us forward into a new space.
Scale. Scale is about proportions - how the sizes and shapes of things relate to each other. A 3 x 6-foot island bed floating in a half-acre sea of lawn will be seriously out of scale. The same will be true of a dwarf apple tree located in front of a two-story colonial house. Most scale problems are due to skimpiness, such as beds and paths that are too narrow, or plantings that are too small and tentative. If in doubt, err on the side of boldness and generosity.
Rhythm. By repeating plants and materials, you can produce a sense of rhythm, order, and predictability. Too much repetition is monotonous, but, as in music, variations on a theme are pleasing. You may want to repeat certain distinctive plant materials, such as the spearlike foliage of an ornamental grass or the velvety gray of lavender or santolina. Repeating splashes of color will also establish a rhythm in the garden and help to guide the eye. But don't be a slave to repetition. The best gardens always leave room for the unexpected—a giant pot of agapanthus, a whimsical birdhouse in a tangle of morning glories, or a blood-red rose tumbling over a stone wall.
Symmetry and balance. Humans seem to be naturally attracted to symmetry—toward creating perfectly balanced features. Our bodies are symmetrical, as are the cars we drive, the arrangement of windows in our homes, and often the shrubs that flank the front door. Used judiciously, perfect symmetry can be a powerfully appealing design technique. But when overused it can become stiff and boring. The natural landscape, which we also find visually pleasing, is not governed by symmetry. In nature, something more subtle is at work, something artists and designers refer to as balance. Balance is an essential factor in garden design. It refers to visual weight: a birch clump balanced by a large bed of hosta; a brick pathway balanced by a wide swath of lawn; orange Oriental poppies balanced by deep blue lupines. In these examples, the two elements are not identical in size, shape, or color, but there is a response from each side that balances the other. Successful garden design incorporates both symmetry and balance.
One thing great gardens share is a sense of place. Entering them is like entering a home—you are wrapped in a particular environment that is very different from the world outside. As in a home, the walls, roof, and floor help give a garden its unique character. When designing your own garden, you can use these aspects to create "rooms" in which plants are arranged in a context rather than floating in space.
Walls. English flower borders almost always have a background behind them. In England, this is usually a tall stone or brick wall or an evergreen hedge. The backdrop serves to stop your eye from roving and allows you to focus on the intended view. Most American gardeners don't make use of this very effective technique, and our gardens often get lost in the larger scene. Whenever possible, anchor your garden by placing something behind it: a structure, a fence, or a planting of shrubs. Remember to keep it simple. The objective is to direct the eye to the foreground, not create a competing element.
Roofs. Though there are plenty of very successful gardens that are totally exposed to the sky, most of us are naturally attracted to more sheltered, intimate spaces: a garden that's been carved out of a woodland or is nestled beneath an ancient apple tree. We are, for the same reason, drawn to arbors, bowers, allees, and pergolas. The roof need not cover your entire garden. Including the experience of enclosure somewhere in your garden—it can be as simple as an arbor at the entrance—will help to create that sense of being in a special environment set apart from the rest of the world.
Paths. Paths lead us through a garden and link one area to another. Paths in themselves are an age-old comfort, showing us the way we are to travel, assuring us of a progression that is safe and intentional. The paving material and the way the paths are laid out can help define the style of the garden. A meandering pathway made of flat stones spaced several inches apart will have an intimate, informal feel; a wide brick path suggests neatness and order; a broad path of closely mown lawn conveys grandeur and expansiveness. Paths also create edges that suggest where new plants or even entire gardens could be located.
Plants themselves can be important design elements, though few gardeners actually use them this way. The arching branches of a well-pruned cherry tree can frame an entire garden. The repetition of the spiky foliage of Japanese iris can be used to unify a long border. If you take the time to notice and experiment with the form, texture, and color of plants, you will discover a whole new palette of design elements with which to work. form. This is a three-dimensional consideration that takes into account the shapes and volumes of the plants in your garden.
A variety of different forms makes a garden interesting, but too much diversity can create visual confusion. Trees and shrubs often have characteristic forms that should be carefully combined to avoid clashing. Flowers, too, have characteristic shapes: the rounded heads of alliums, verbena, and globe thistle; the vertical spikes of delphinium, snapdragons, and veronica; the diaphanous look of baby's-breath and Queen Anne's lace; the strong architectural lines of a 5-foot martagon lily. You can experiment by grouping plants with the same form into a drift, or by repeating a pleasing composition of different forms several times.
Texture. Plants have a tactile quality that can be used as a valuable design tool. Think about how the glossy leaves of holly, magnolia, and roses contrast with the suede-like foliage of lamb's ears, heliotrope, and coleus. Or how the fat and fleshy leaves of a sedum differ from the needle-like foliage of rosemary or the quilted leaves of a blue-green hosta. Flowers also provide textural interest. They can be rich and velvety like a rose, or as thin and translucent as a poppy. Even tree bark contributes textural interest - especially during the winter months.
Color. Entire books have been written about using color as a design tool. You can approach color as a technician, using the color wheel to create harmonious combinations, or you can use your own eyes and emotions to guide you in creating the look and feel you want. Combining colors in new and interesting ways offers a lifetime of exciting possibilities.
As a general rule, red, orange and yellow are colors that jump out at you. They are lively and stimulating, and give the impression that they are closer to the eye than they actually are. If you plant too many hot-colored flowers, and don't balance them with cool-colored, less assertive plants, your garden will be a jumble of blaring trumpets. Green, blue, and violet are cool colors. In the garden these flowers create a more soothing, restful feeling, and tend to recede into the distance.
Visiting other people's gardens may be the best source of design inspiration. Take along a camera or sketch pad to capture features that you find particularly successful or appealing. Notice when some of the design techniques described above are being used. Don't be afraid to ask questions about what the gardener was trying to achieve.
Glossy picture books of gardens run a close second for design inspiration. They have the distinct advantage of being available for perusal year-round. Use sticky notes to mark images that capture your attention, then go back and review your choices to see where the similarities lie. Comparing and contrasting different types of gardens can be very useful in helping you decide what sort of look attracts you. If you are gravitating toward a theme garden (colonial, Japanese, Southwestern, English cottage), you'll find dozens of books that illustrate the design features and techniques that distinguish these styles.
Some garden design books include complete planting plans that are theme-oriented, or are specific to a certain type of site. They usually provide a site plan, a planting list, and an elevation drawing that shows what the garden will look like at eye level. You can follow the plan, or pick and choose the elements that appeal to you.
Creative gardeners read garden design books the way creative cooks read recipe books. Don't feel compelled to follow the garden design verbatim. You can lift ideas here and there, and combine them into your own unique expression.
Some purists believe that ornamentation—trellises, furniture, sculpture, and decorative planters—has no place in the garden. Others fill their gardens with so many decorative elements that it can be difficult to find the plants. Used judiciously, the furnishings and decorative features that you incorporate in your garden help give it style and character.
Decorative elements can be characterized as formal, informal, or somewhere in between. This has something to do with what the piece is (a whirligig versus a Japanese lantern), but also what the piece is made of. Fanciful wooden birdhouses and split-rail fencing have a casual, country feeling; whereas a bronze nude or a Grecian urn are more elegant and formal. When choosing decorative elements for your garden, the challenge is to select items that appeal to you, and that will also fit harmoniously with the style you are trying to achieve and any other decorative objects that you already own.
For many gardeners, there's nothing like a full perennial border with a crisp edge of lawn.
Perennial plants are the backbone of nearly every flower garden. Unlike annual plants, which must be replanted each spring, herbaceous perennials die to the ground at the end of the season, and then regrow from the same roots the following year. People grow perennial flowers because they are such easy-care, dependable performers, and because they offer an enormous variety of color, texture and form. Here are the basics of garden design, plant selection and care.
The lifespan, bloom time, culture and form of perennial plants varies greatly. Some species, such as lupines and delphinium, are so called "short-lived" perennials, with a lifespan of just three or four years. Others may live as long as fifteen years, or even, in the case of peonies, a lifetime. Bloom time may last for only two weeks each year, or may extend over two or three months.
Some perennials, such as primroses, require deep humusy soil and plenty of shade, while others such as threadleaf coreopsis and cushion spurge wither away unless they grow in well-drained soil and full sun. Some perennials contain themselves in a nice, neat mound, while others, such as gooseneck loosestrife, will take over your entire garden. Some species should be cut back in midsummer, while others, such as hybrid lilies, may die if you remove their foliage.
There are so many different species and cultivars of perennial flowers to choose from that few people ever become completely familiar with all the options. For the perennial gardener, books are an invaluable resource. They provide photographs for identification (and inspiration!), cultural information, a description of growth habits, bloom time, color and characteristics of special cultivars. Invest in a good how-to book that has cultural information, and a color encyclopedia to help you identify plants and plan your selections.
What's in a Name?
It may be hard to believe, but scientific plant names are used to avoid confusion, not create it. They are developed by taxonomists to ensure that the same plant is called the same name throughout the world, regardless of language. Scientific plant names are usually a combination of Latin and Greek.
Common names, such as "bleeding heart," are often used to refer to all the plants in a genus and are useful unless you want to ensure you are purchasing a 24-inch high, spring-blooming bleeding heart (Dicentra spectabilis) rather than the ever-blooming species known as the fringed bleeding heart, which is only 12 inches high (Dicentra eximia). To learn more about botanical names, look for a copy of Gardener's Latin by Bill Neal (Algonquin Books, 1992).
Dicentra spectabilis 'Alba': (old-fashioned white bleeding heart)
Dicentra: The first name is the genus. It is always capitalized.
spectabilis: The second name is the species. It is not capitalized.
'Alba': The third name, which appears in single quotes, is the cultivar (cultivated variety).
Fellow gardeners are another great source of information about perennials. They can give you firsthand details about bloom time, height, hardiness and cultural requirements, and, if you visit their gardens, you can also see for yourself what the plants really look like up close. Nothing beats seeing a plant in a garden setting, where you can observe how it is being used. You may even go home with some pass-along plants for your own garden.
There's just no way to know how a plant will do for you unless you give it a try. If it turns out to be too tall, the color is wrong, or the plant doesn't thrive, you can always move it and try something different.
Few if any "perennial gardens" contain only herbaceous perennials. Woody plants, such as shrubs, roses, and trees, are often incorporated to provide a backdrop for the perennial plants, or are used to fill in and give mass to the bed or border. Many gardeners include annuals or biennials in their perennial gardens to provide splashes of dependable color throughout the season. Bulbs are added for early spring color and ornamental grasses for their interesting textures and late-season beauty.
Traditionally, perennial gardens have been laid out in one of two ways: a border or an island bed. A border is typically a long, rectangular flower bed that is about two to four feet deep. The classic English perennial border, which was so popular in the first half of the 20th century, was often as much as eight feet deep and 200-feet long. But for most home gardeners, a better size is about three feet deep and about 12 to 15 feet long.
Borders are usually viewed from only one side, and are located in front of a backdrop. This backdrop may be created with shrubs, a hedge, a fence or a stone wall. A well-defined front edge is important. You may design a solo border, or a matched pair. When selecting plants, keep in mind that borders usually look best when there is a repeating theme of plants and colors.
An island bed is a garden that floats in a "sea" of lawn. The shape is irregular, with gentle curves and no sharp corners. It is usually designed to be viewed from all sides, with the tallest plants positioned along the center line of the bed, and the shortest plants around the edges. Island beds look best when they are generous in size. A good size for an island bed is 8-by-15 feet, with the tallest plants reaching a height of about five feet.
Of course perennial flower gardens sometimes look nothing like a traditional border or island bed. Rock gardens break all the rules, for the objective is usually to create an irregular, natural-looking rock outcropping where tiny alpine plants can be featured.
Shade gardens are often irregularly-shaped, because they follow the natural shade patterns of the trees above. Another emerging style for perennial gardens is the large, free-form garden. In this case, the garden is defined by a series of meandering paths that lead the viewer right into and then through the plantings. Perennial flowers can also be mixed in among shrubs, planted around your mailbox, used in woodland or streamside plantings, or even planted in containers.
The appearance of a perennial garden depends as much upon the shapes of your plants and how they are arranged, as upon their colors.
Height: You'll want to place the tallest plants in the back of the border, or in the center of an island bed, then work down in height, ending with the shortest plants around the edges of an island bed or the front of a border. Books and labels usually list the average mature height for a plant in bloom. Remember that many plants hold their flowers well above the foliage. This means that when the plant is out of bloom, it may be much shorter than the specified height.
Heights are also an average. When grown in poor, dry soil, a plant may be only half as tall as the same plant grown in rich, moist soil. Be prepared to move your plants around once you see how tall (or short) they really grow. Even the most experienced gardeners rearrange their plants (usually more than once!).
Width: A plant's width, or spread, is just as important as its height. Width figures given in books or on labels are also an average. The actual width of a plant will vary depending on soils, geographical location and the age of the plant. Be careful about locating slow-growers very close to rapid spreaders. The former may all but disappear by the end of the first growing season.
Spacing: Patience is a virtue, but when most people plant a perennial garden, their goal is to create a full effect as soon as possible. The challenge is to plant thickly, but not break the bank, or create a crowded, unhealthy situation two or three years down the line. When planting a grouping or "drift" of the same kind of plants, you can put them closer together to create a massed look more quickly.
Another trick is to place short-lived plants between slower-growing, long-lived plants. Most peonies, for example, have an ultimate spread of three feet, but it may take seven years for them to reach this size. While you're waiting, you could interplant with Shasta daisies, a fast-growing, short-lived plant that will provide a full look and plenty of flowers while the peonies get themselves established.
Drifts versus specimens: A garden planted with groupings of five or more plants of the same variety will display drifts of repeating colors and textures. In this type of garden, plants are used primarily as design elements that add up to a pleasing and integrated visual effect.
At the opposite end of the spectrum is the collector's garden, filled with onezies and twozies of all different kinds of plants. These are the gardens of people who simply love plants and want to have one of everything. The look of this type of garden may be a jumble of colors and textures, and maintenance is usually more challenging, but these gardens are about plants first, and design second.
When it comes to deciding which perennials to plant, most of us are not very deliberate about our choices. We succumb to a luscious photo in a catalog, stumble upon an irresistible beauty at the nursery, or a neighbor sends us home with a bag full of cast-offs. If you ever do set out to make an informed and deliberate choice, here are some of the things that you should think about.
Your site: Perennials, like all plants, will live longer and be healthier and more floriferous if they are planted in a location that suits them. Does your garden have sandy soil or is it heavy clay? Is it in the sun or shade? Is the soil moist or droughty? Is the pH high, low, or neutral? Is the site flat, gently sloped, or steep? A good reference book can help you figure out which plants will probably be happy in the growing conditions that you can provide.
Hardiness: If a plant is not hardy in your growing zone, it will not survive the winter. If you don't know which zone you live in, check a USDA Hardiness Zone Map. Though knowing your zone is very important, altitude, wind exposure, soils and snow cover can have a dramatic impact on plant hardiness, effectively shifting the hardiness rating for your garden by as much as a full zone.
For best results, choose plants that are well within your zone. You will probably be tempted by those that are at or even just beyond your growing zone. If you can afford to take the gamble (financially and emotionally), it can be very rewarding to discover that you can grow a couple of Zone 5 plants in your Zone 4 garden. Where snow cover is not dependable, a winter mulch of leaves or straw can help marginally hardy plants survive a cold winter. Well-drained soil is also a benefit. Heavy, wet soils will often heave and damage plant roots.
Northern gardeners concern themselves with the minimum temperatures that a plant will tolerate, but Southern gardeners must also pay attention to zone ratings. Many popular perennials, including lupines, peonies, and garden phlox, must be exposed to a period of subfreezing temperatures to produce a good display of flowers. Other perennials will simply not tolerate long periods of heat and humidity.
Color: In working with color, aim for a balance of integration and contrast. Too much of the same color can be monotonous, yet a cacophony of different colors can be jarring rather than pleasing to the eye. You may want to organize your garden around one color; or choose a theme such as pastels, cool colors, or hot colors. You can also experiment with different color themes in different parts of your garden—hot colors by the front door and cool colors in a quieter part of the yard.
Remember that few perennials are in bloom for more than a couple of weeks each year. Most of the time, plants are green, and it is their leaf form and foliage texture that are the "color" in your garden.
Bloom time: A perennial may be in bloom for two weeks a year or for as long as three months. If your objective is all-season color, choose several plants from each bloom season. When selecting plants for a spring garden, concentrate on those that bloom during April and May. After that peak, the garden may lack color for the rest of the season, but you will have achieved a spectacular spring display. For best effect, group at least two or three different varieties of plants together that will bloom at the same time.
Remember that specified bloom time is only an average. In California, April may be the peak bloom time for bearded iris, yet in Vermont, the same plant will not bloom until early June. Recording the bloom times of various perennials in your garden will become an invaluable reference. No book, no matter how good, will be as accurate as your own observations about when plants bloom and how they perform in your own garden.
Seedling, potted or field-grown: When purchasing perennials, try to get the largest, most mature plant that you can afford. The bigger the plant, the more quickly it will fill out and the sooner it will begin blooming. Typically plants are available in pot sizes ranging from 3-inch diameter to 12-inch diameter. Pot-grown perennials can be planted from spring through fall, and will suffer minimal transplant shock.
Some mail-order companies ship their plants bareroot (without soil). Bareroot perennials are usually available only in early spring when the plants are still dormant. The roots must be kept moist, and the plant should be put into the garden as soon as possible (within a couple of days). Once the plant is in the ground and has emerged from its dormant state, it will take hold relatively fast.
A few local nurseries still offer field-grown perennials. These plants are dug up when you come for them and they need to be transplanted immediately (within a few hours) to minimize transplant shock. Field-grown perennials are usually the largest and most mature plants around, but today most nurseries only offer container-grown perennials.
Vigor: Vigor can be good, but it can also create problems. Plants that are too vigorous can invade neighboring plants and gradually take over your entire garden. Determining a plant's propensity for invasiveness can be difficult, because poor growing conditions can render a normally invasive plant relatively tame, whereas in fertile soil, a normally restrained plant may exhibit invasive tendencies.
Look closely at plant descriptions and be wary of those described as "vigorous." This may be a euphemism for an invasive plant that you'll wish you never set eyes on. Perennials with a reputation for invasiveness include: bamboo, Macleaya cordata (plume poppy), Physostegia virginiana (obedient plant), Monarda (bee balm), Artemisia ludoviciana (Silver King artemisia), Lysimachia clethroides (gooseneck loosestrife), Tanacetum vulgare (tansy), Aegopodium (goutweed), and Boltonia asteroides.
Though most flowering perennials are dependable, easy-care performers, all perennial gardens require some maintenance. Here are the eight most important steps to ensure a healthy and floriferous garden:
Most perennials are not heavy feeders and they will be happy with one spring application of a low-nitrogen, high-phosphorus fertilizer (5-10-5). For established plantings, scratch in a good handful of fertilizer around each plant. Annual or biennial applications of aged manure or finished compost will restore trace elements and improve soil texture and water retention.
A perennial garden does not require as much water as a vegetable garden. Depending on where you live, if you select plants suited to your site, and mulch them well, you may not need to water at all. If you live where summers are very dry and you do need to water, try to water deeply and avoid getting water on the foliage (soaker hoses and drip irrigation systems are great for perennial gardens).
By early summer, a densely planted perennial garden will shade out most weeds. But a new garden, a spring garden or a garden that is more sparsely planted, will benefit from some kind of mulch. The mulch will keep weeds to a minimum and help retain moisture in the soil.
The aesthetics of the mulch are as important as the function. Your garden will look best with a finely textured material such as shredded leaves, dry grass clippings, peanut shells, cocoa hulls or shredded bark. Big chunks of bark, newspaper or straw will overpower your plants.
4. Neat Edges
A neat, cleanly defined edge between your lawn and flower bed will give your garden a professional look. You can achieve this in one of two ways: get a nice sharp edging tool and recut the edge several times during the growing season; or install some permanent edging. A defined edge will also help keep grass and weeds from growing into the bed.
Some kinds of perennials, including asters, chrysanthemums, phlox and salvias, benefit from being pinched back. Pinching creates a bushier plant that produces more blooms and is less likely to flop over. Pinch back the growing tips--using thumb and forefinger--once or twice during late spring. Not all kinds of perennials should be pinched. If in doubt, pinch a little here and there, and see what happens.
Some plants drop their spent flowers and seed heads. Others hold onto them for months, or even right through the winter. Removing spent flowers will keep your plants looking their best, and it often stimulates reblooming. It also prevents plants from expending their energy on seed production. After bloom, some plants should be shorn rather than deadheaded. This is true for creeping phlox, nepeta, hardy geraniums, daisies, pinks and lavender.
Many tall or weak-stemmed plants need support when they reach blooming size. Delphiniums and hybrid lilies are two prime candidates. But other, shorter plants can also benefit from some kind of support. Supports should be as invisible as possible. For individual stems, you can use bamboo canes. For entire plants you can use wire support rings. For loose and airy plants, try using a few thin branches. For best results, put the supports into position in early spring. That way the plants will hide the supports as they grow.
If your perennials are happy, most of them will need to be divided every few years. They may become too large for the space; the center or oldest part of the plant may die out leaving a bare middle; or the growth may become so dense that the plant is no longer blooming well.
Use a shovel to remove the entire plant from the garden and place the root ball on a tarp. Then you can either pry the plant into pieces using two forks, tease the pieces of the plant apart into different sections, or use a shovel or knife to cut the plant into several pieces. Plants should not be divided when they are in bloom or in full growth. In all but a few cases, this is a job for early spring or late fall.
Customer photo by Therese of Lusby, Md.: Bearded (or German) Irises have some of the most showy blooms. "This hillside of Bearded Irises consists of many varieties and cultivars. I like to watch the morning sun pass through them, illuminating them like glass."
Irises are one of the earliest blooming and easiest perennial flowers to grow. Most of the more than 300 species worldwide are hardy throughout the U.S. and are widely adapted to various soil and sun conditions. By combining different types of irises, you can have them in bloom from early spring right into the summer. And if you add a few repeat-blooming bearded irises, you'll also enjoy flowers in late summer and early fall.
The show begins with Dwarf Irises (Iris reticulata), which are among the first bulbs to bloom in spring, They are followed by the late-spring and early-summer varieties, which bloom in this general order:
Dwarf Irises (I. reticulata and I. danfordiae): These irises grow from bulbs planted in fall. They produce 6-inch-tall, blue, yellow or purple flowers in early spring in zones 4 to 9. Over the years, these bulbs will naturalize into nice clumps of bloom; just be sure to plant them in a well-drained location.
Bearded Irises (Iris germanica and hybrids): Bearded Irises, also known as German Irises, have a fleshy root that's called a rhizome, which grows right at the soil surface. The flower stalks range in height from 8 to 40 inches, depending on the variety, and are hardy in zones 3 to 9. Cultivars are often divided into groups by height, ranging from dwarf bearded to tall bearded. Blooms come in a range of colors, and the plants have stiff, upright leaves. All make good cut flowers. In recent years, fragrant varieties have become available. Some varieties, called "reblooming irises," bloom in early summer, followed by a repeat in late summer or fall. In mild climates, they might repeat more than once.
Bearded irises are typically planted in late summer or early fall. For complete planting details, see Growing Bearded Irises.
Siberian Irises (I. siberica): Siberian iris plants grow to a height of 2 to 4 feet tall and are hardy in zones 3 to 9. They feature mostly blue, white and violet flowers and have tall, grass-like foliage. Siberian irises grow well in cool, wet conditions and, though they thrive in full sun, they can also tolerate some shade.
Plant about 1 inch deep in full sun to part shade. Divide in late summer, but only when the center of the clump has stopped growing.
Louisiana Irises (I. fulva, I. giganticaerulea and I. brevicaulis): Hailing from the Gulf Coast, these 2- to 4-foot-tall irises are water lovers and will be happy growing at a pond's edge or a wet spot in your yard. They also grow well in acidic soils. They're rot-resistant, hardy in zones 5 to 9, and feature a broad range of flower colors, including a true red. Foliage is tall, upright and sword-like.
Japanese Irises (I. ensata): Like Louisiana irises, this species thrives in wet, acid, mucky soils. For instance, you can grow them along the edge of a pool or stream, or in a partially submerged pot in a water garden. They're hardy in zones 5 to 9, producing 2- to 3-foot-tall flower stalks with a range of flower colors from white to lavender. Foliage is ribbed and upright. Japanese irises have the largest flowers of the iris species. Once the plant has formed a large clump, it can be divided.
Dutch hybrids (I. hollandica): These irises—also called Beauty Irises—are perfect for cutting gardens. Often grown as annuals, Dutch iris hybrids grow from bulbs that can be planted in fall (where hardy, zones 5 to 9) or spring. Orchid-like flowers bloom from late spring to early summer. This group of irises has an especially wide range of colors and patterns. Unlike the foliage on other types of irises, these hybrids have grass-like leaves.
Plant in full sun to full shade, 4 inches deep. Tip: Zone 5 gardeners should add a 2-inch layer of mulch in fall.
Healthy iris plants may become crowded and need dividing after 3 to 4 years. A decrease in blooms usually indicates that it is time to divide. Divide bearded irises in summer, roughly two months after blooming. Other irises are best moved in early spring or fall.
Before dividing bearded iris, cut back the foliage to one-third its original height. Dig the clumps and separate healthy new rhizomes from the older, less-productive rhizomes toward the center of the clump. Discard any rhizomes with holes (from insect damage, see Iris Borer, below) or soft spots. Cut the new rhizomes so each has at least one set (fan) of leaves. Plant them as described above, leaving 12-18 inches between rhizomes.
Other irises (such as Siberian and Japanese) should be completely dug up and then the rootball can be divided using a sharp spade or knife. Discard any dead or weak areas and then replant roughly half as much plant as you removed.
The most serious Bearded Iris pest is the iris borer, which is usually a problem confined to gardens east of the Rockies. The eggs overwinter on iris leaves and hatch in spring, tunneling into the leaves and eventually burrowing to the rhizome. The leaves of infected plants have yellow streaks and detach easily from the rhizome. The rhizome may be mushy or have small holes from burrowing larvae.
To control iris borer, foliage and debris around the plants should be removed in the fall. Discard any infected rhizomes when dividing. Remove and destroy any infected foliage that appears during the growing season.