Arranging Your Plants
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.

How to select plants
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. (You can use the Zone Finder, above left.) 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. During the winter, heavy, wet soils can heave and damage plant roots.

Northern gardeners concern themselves with the minimum temperatures that a plant will tolerate, but Southern gardeners must pay attention to the upper end of zone ratings. Many popular perennials, including lupines, peonies, and garden phlox, will not perform well in warm climates. They 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. Keep a record of when various perennials bloom and you'll create and 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 plants bareroot (without soil). Bareroot perennials are usually available in spring and fall. 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
Vigorous plants can be good, but they 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.

Maintaining a perennial garden
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:

1. Fertilizing
Most perennials are not heavy feeders and they will be happy with one spring application of a low-nitrogen, high-phosphorus, all-purpose granular 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. Natural soil amendments for perennial gardens include greensand, kelp meal and rock phosphate.

2. Watering
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).

3. Mulching
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.

In a perennial garden, 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. The big chunks and coarse texture 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.

5. Pinching
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.

6. Deadheading
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 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.

7. Staking
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 grids or 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.

8. Dividing
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.

Perennial Tips

• When planting a new perennial garden, prepare the soil well at the outset. That may be your only opportunity to loosen the soil, remove rocks, and add organic matter.

• If you start plants by seed, put your first-year seedlings in a "nursery bed" rather than directly into your flower garden. They will not bloom or have much of a presence until their second year anyway, and a nursery bed will allow you to keep a better eye on their performance.

• Eventually, most perennials will need to be divided. Do it in early spring, when new growth is only a few inches high. If you miss your chance in the spring, wait until fall.

• Keep newly transplanted perennials well watered for the first few weeks. Water deeply to saturate the entire root ball and establish good contact between the roots and the surrounding soil.

• Most perennials prefer a pH of about 6.5, although, some prefer more alkaline or acidic soil. If you have trouble with a particular plant, check its pH requirements and the pH level of the soil in your flower garden.

• If your plants look stressed during the growing season, or if you see disease or insect damage, feed your plants with a quick-release organic fertilizer (try a blend of seaweed and fish emulsion).

• All plants die eventually, and some will die sooner than others, no matter what you do about it. If a plant performs poorly, try moving it to a different location. If it still is not happy, give it away or send it to the compost pile.

• When designing a perennial garden, think about how you'll get access to your plants to stake, deadhead, or divide them. Flat rocks can be used as stepping stones within the garden. A walkway created at the back of a border will be hidden during the growing season, but will make the bed accessible for spring and fall chores.

Unlike annual flowers, which must be replanted each spring, perennials return to bloom again year after year. But while you can depend on annuals to bloom non-stop from early summer until frost, most perennials have a specific bloom period that lasts from two to six weeks. This means that without a little planning, your perennial flower garden could be wildly colorful in early summer and then nothing but green for the rest of the season.

By choosing a few plants from each of the following bloom-time categories, you can keep your garden colorful from May through September. Note that actual bloom time will vary somewhat depending on growing conditions and where you live.

Early Spring Bloomers Old-fashioned Bleeding Heart (Dicentra) Woodside Columbine (Aquilegia) Eroica Bergenia (Bergenia cordifolia) Helleborus Orientalis (Helleborus) Lungwort (Pulmonaria)	MidSpring Bloomers Barrenwort (Epimedium) Bleeding heart (Dicentra) Perennial geranium (Geranium) Globeflower (Trollius) Lily-of-the-valley (Convallaria majalis) Speedwell (Veronica)
Early Summer Bloomers Bellflower (Campanula) Blanket Flower (Gaillardia) Butterfly weed (Asclepias tuberosa) Coral bells (Heuchera) Daylilies (Hemerocallis) Geum (Geum) Globe thistle (Echinops) Japanese Iris (Iris ensata) Peony (Paeonia) Salvia (Salvia nemerosa 'Cardaonna') Siberian iris (Iris sibirica) Speedwell (Veronica)	Early Summer Bloomers Astilbe (Astilbe) Daylilies (Hemerocallis) Gayfeather (Liatris spicata) Goat's beard (Aruncus dioicus) Lilies (Lilium) Mallow (Malva) Meadow Rue (Thalictrum flavum) Meadowsweet (Filipendula purpurea) Mullein (Verbascum) Speedwell (Veronica) Spiderwort (Tradescantia) Torch lilies (Kniphofia)
Late-Summer Bloomers Balloon flower (Platycodon grandiflorus) Hostas (Hosta) Goldenrod (Solidago) Ligularia (Ligularia) Toad Lily (Tricyrtis formosana)	Early Fall Bloomers Purple coneflower (Echinacea purpurea) Sedum (Sedum)

How many times have you seen a bee in your garden, buzzing from one snapdragon or squash blossom to another? At each visit the bee almost disappears into the flower as it uses its long tongue to lap nectar hidden deep within the flower. When it backs out, tiny bits of pollen are stuck to its hairy body.

Gardening for pollinators allows us to understand and appreciate a part of nature we usually don't notice: the insects. Once you start paying attention, you will find a whole world that is even more complex, fascinating and important than any of us realize.

Through simply looking for food, thousands of species of bees and other insects and animals help plants to reproduce. Of the estimated 240,000 flowering plants worldwide, 91 percent require an insect or animal to distribute their pollen in order to set fruit and seed. That includes one-third of all crops grown for people, including citrus fruits, almonds, berries, squash and cotton.

Most people recognize that bees are important pollinators. But many species of butterflies, bats, birds, moths, flies and even mammals are also pollinators. These creatures are so essential to reproduction that most of the world's plant life could not exist without them.

Despite the critically important service they provide, pollinators have been taken for granted and they are in jeopardy. According to the U.S. Department of Agriculture, we are facing an "impending pollination crisis," in which both wild and managed pollinators are disappearing at alarming rates.

In the U.S. the number of honeybees has decreased by 25 percent in the past decade due to a parasitic mite. Meanwhile, wild pollinators are threatened by habitat loss, pesticide use and disease -- just as researchers are learning how valuable and efficient many of these pollinators are.

You can help improve the plight of pollinators, starting in your own backyard. Just imagine a patchwork of pollinator gardens all across the country -- building diverse communities of beneficial insects!

5 Ways Backyard Gardeners Can Help
1. Plant nectar- and pollen-rich flowers.
The most important step you can take is to plant a pollinator-friendly garden. Choose nectar- and pollen-rich plants, such as wildflowers and old-fashioned varieties of flowers. A succession of blooming annuals, perennials and shrubs is best so nectar and pollen are available throughout the growing season. Also, include plants like dill, fennel and milkweed, which provide food for butterfly larvae.

With a few, well-chosen species, any size garden can attract and support pollinators -- from a wildflower meadow to a windowbox. Researchers in Tuscon, Ariz., have found that communities of bees can sustain themselves for long periods of time in small vacant city lots.

A patchwork of pollinator gardens in neighborhoods, cities and rural areas around the country could provide enough habitat to restore healthy communities of beneficial insects and pollinators.

2. Go organic.
Many pesticides -- even organic ones -- are toxic to bees and other beneficial organisms. There's no need to use powerful poisons to protect your garden from insects and diseases. In the short term they may provide a quick knock-down to the attackers, but they also kill beneficial organisms. In the long term, you expose yourself, family, pets and wildlife to toxic chemicals, and risk disrupting the natural ecosystem that you and your garden inhabit.

All things considered, an organic approach is both safer and more effective. By applying the simple principles of ecological plant protection, you can work with nature to control pests and diseases, enjoy a healthier garden and harvest and protect pollinators and other beneficial insects.

If you do apply pesticides make sure you apply them carefully and selectively. To protect pollinators, do not use pesticides on open blossoms or when bees or other pollinators are present.

4. Provide food and water.
A pollinator garden will provide pollen and nectar. Consider adding special feeders to help attract hummingbirds and butterflies.

Bees, birds and butterflies also all need water. Install a water garden, a birdbath or a catch basin for rain. Butterflies are attracted to muddy puddles which they will flock to for salts and nutrients as well as water.

5. Backyard beekeeping
You don't have to live in the country to keep bees. All you need is a little space, a water source, plenty of nearby flowers for them to visit, and a willingness to learn. Keeping a beehive or two in the backyard used to be a common practice. Maybe it's time to bring back this old-fashioned hobby. It does require equipment and some specific knowledge. But it's nothing an interested hobbyist can't handle.