Nothing dresses up a home's exterior like a few well-placed and well-designed flower beds. Flowers can make any home more inviting. The splash of color and the sweep of texture these living things bring to a yard also speak to the vitality and optimism of the occupants.

While flower gardening is not difficult and can be learned as you go, there are a few things to consider before you begin. Let's start with the most basic factors: how to choose flowers, where to plant them, how to plant them, and how to keep them thriving.

Annuals Or Perennials?

As the name implies, annuals are flowers that die off with the first cold snap. They may re-seed themselves, but this year's plants won't be around next spring. As with most short-lived things, they are flashier than those that can take their own sweet time. They offer vibrant, season-long colors?to better attract pollinators?and because they're in such a hurry, they're fairly easy to grow. As seeds and seedlings, they're also affordable.

Perennials are another matter. In general terms, a perennial is any plant -- including trees, shrubs, turf grasses and "herbaceous" flowers -- that lives at least three years, though most live a good deal longer. In colder climes, the perennial loses its top growth with the first hard freeze, but its root system stores enough energy for a full recovery the following spring.

With some exceptions, perennial colors are softer, more muted. Perennials almost always bloom for shorter periods of time than annuals, with a few blooming in spring and the rest in summer or fall. Relieved of the urgency of a short life, perennials can invest in more interesting structures and profiles. In design terms, they offer greater textural interest.

While perennials cost more up front, they don't usually require much additional expense. Plant them once and you won't have to replant for years. There is also a wider variety of perennials to choose from, with something for every climate and taste. And because perennials need only a rise in soil temperature to spring to life, they enjoy a practical head start on annuals, which require, beyond a warming soil, the efforts of the planter.

Considering what each has to offer, many homeowners choose a combination, planting the bulk of their garden in low-maintenance perennials, with a few brightly colored annuals serving as accents. This is the option we've chosen here. While starting off with lots of perennials is a more costly approach, you could easily spread the expense over several years by starting with more annuals and gradually replacing them with perennials.

Plant And Site Selection

While there are literally hundreds of choices when it comes to annual and perennial flowers, geography, regional climate and site conditions are limiting factors. For example, a flower garden in Tucson will be different than a garden in Charleston, and the Charleston garden will differ from one in Bozeman. An open, sunny lot will require different plant and design choices than a smaller, wooded space. Similarly, a formal English-style garden will dictate plants that are less invasive than those suited to an informal garden.

Still, choosing plants that will work for you need not be overwhelming. You probably already know the look you're after, based on neighborhood examples, and a few design guidelines can help fill in the blanks. For more specific information, visit your local garden center or nursery. These suppliers can provide practical advice on locally favorable plants, and many offer design help from certified designers. Often the design fee is waived when you spend a given amount on plants and garden supplies. Your county's USDA Cooperative Extension office is another good source of information.

When it comes to choosing the best bed sites, look for fairly level, well-drained spaces away from rough traffic. The space next to a sidewalk is fine, for example, but the space behind a basketball hoop is probably not. Wind is another qualifier. Taller, more vulnerable plants are better suited to the leeward sides of fences and houses. And because there are more flowers that thrive in sunlight than shade, a space with at least some sun will expand your options.

As for soil conditions, unless you have exceptionally loamy soil, plan to improve it before planting. The goal is to create a fluffy, absorbent soil at least 8 in. deep, usually by tilling in compost, dried manure and peat moss. These materials keep the soil from becoming so dense and compact that it stifles root development and sheds water.

Design Considerations

Flower gardens take two forms: They're either borders or beds. Those out in the open, with exposure on all sides, are called beds. Those that skirt buildings or other landscape features are called borders.

Because beds can be viewed from several angles, it makes sense to plan them with the tallest plants near the center, with successively shorter plants extending toward the perimeter. Borders, on the other hand, are usually viewed head-on, so the taller plants should serve as a backdrop for shorter, more colorful varieties. Many designers suggest that borders should be twice as wide as the height of the tallest plants. And where a border wraps around a corner, plants that are heavier in appearance can help soften a home's hard edges.

Flower gardens can be formal or informal. Formal gardens are generally composed of adjoining or overlapping geometric shapes -- squares, circles, triangles and rectangles -- and are usually divided or bordered by straight footpaths. The formal garden should have an orderly feel, with a sense of compensating balance, all achieved through shape, color and repetition.

Because of their geometric underpinnings, formal gardens are fairly easy to design and implement for the beginning gardener. Just lay out the patterns on graph paper, paying particular attention to balancing prominent features, and scale the whole thing to size. Then choose plants that will fit each space. Most formal gardens include annuals and perennials, anchored by a few ornamental trees and shrubs that lend themselves to topiary shaping.

Because formal gardens are contained, the plants you choose should mature in predictable shapes and sizes. Avoid sprawling plants and those that invade adjoining spaces through root propagation or surface runners. Perennials that need regular pruning should also be avoided.

Informal gardens are a bit harder to design because they're inherently less orderly. Instead of following geometric patterns, they creep and meander in irregular forms. Instead of choosing flowers that exaggerate or echo geometric shapes, you'll be aiming for a more varied, random?almost wild?appearance. Of course, the problem with randomness is that it comes so close to chaos. To hold the line, choose plants with varied structures, colors and different bloom times, to play off one another, and avoid planting in rows or repeated patterns. Instead, plant some in drifts?tightly grouped sets of similar flowers?again with a random, irregular placement.

Here, too, it makes sense to use the taller plants as backdrops, either bordering a wall or anchoring the center of a bed. In an oblong or kidney-shaped bed, like the one we planted, it also helps to weight the taller, centerline plants slightly nearer one end. Then, anchor the opposite end with brightly colored annuals.

One Plan In Action

We chose to finish two areas in flowers, one a small, shady border and the other a larger, full-sun bed. Our 5 x 10-ft. border skirts the north side of the house and the larger, kidney-shaped bed curves toward a concrete driveway. This sweeping, informal bed, measuring about 11 x 33 ft., serves as a visual counterbalance to the drive, which weights the property heavily to the left. We trimmed each bed with plastic edging and tilled compost into the heavy clay soil. We spent about $500 and took advantage of some design help that was included in the bargain. In any case, this is a job that just about anyone can do.

Begin by laying out garden hose in the rough shape of the bed space. Then move the hose around until you have a shape the fits the yard and suits you. When you have the bed laid out, use a garden spade or a square-nosed shovel to slice into the sod next to the garden hose. To remove the sod, slice it into strips and cut under it with the spade. Then just peel it back.

With the bed area cleared, use the spade to cut a line around the perimeter approximately 6 in. deep. Feed the plastic border into the opening and, pressing the spade against the border's bottom ridge, push it into the ground. Stop when the top tube of border rests just above the exposed soil. Where two lengths of border meet, push them together over the splice tube included with the kit. If you have trouble inserting the tube, lubricate it with liquid dish soap.

To condition the soil, we chose a combination of compost, free from our city landfill, plus a sprinkling of peat moss. Just cover the bed several inches deep in compost and peat moss, and till it in to a depth of about 8 in.

With the bed prepared, set out your plants in their starting pots and move them around until you find the look you're after. Then, dig a hole for the first plant, letting the size of the pot determine the size and depth of the hole. Ideally, the top of the potting soil around the plant should meet the grade of the bed. Clean out the hole with your hands and soak its bottom and sides with water-soluble fertilizer designed for starting plants.

Next, lift the plant from its starter pot and pull some of the roots away from the ball. Set the ball in the hole, spreading the loose roots as you go, and press down firmly on the ball to eliminate any air pockets.

Finally, fill the remainder of the hole with soil, mounding it slightly around the base of the plant. Pack this mound firmly and sprinkle it with another shot of fertilizer. Then, flood the area with water.

Repeat this process until you've planted all your flowers. The only variations will be in the size, and occasionally the location, of the hole. For instance, tiny plants require only a slight depression in the soil.

And when planting in a border, be sure you don't plant too close to the fence or wall. Determine the eventual diameter of the back row of plants and stay at least half that distance away. Finally, cover the ground with at least 3 in. of mulch to retain moisture and discourage weeds.

With your planting finished, there's one more step you might take to encourage a good start. If the flowers you buy have blooms, it helps to pinch them off. This allows the plant to invest less in top growth and more in root development.