The heat is on, and annual flowers have arrived at garden shops, ready to make this summer the most dazzling ever. No other blooms can beat the performance of annual flowers, which bloom from May on, all the way through to the first frost. Plant them now, and enjoy them for months.

Annuals are all the bright marigolds, zinnias, salvias, lantanas, petunias, begonias, verbenas and other blooms sold at garden shops by the truckload in spring and summer for flowerpots and flower beds. They're often already in bloom when you buy them, and they just get bigger and better as the season progresses. They're easy to grow, versatile and lots of fun.

If you've never had a garden before, these showy, reliable plants will make a big impression in a pot by the front door or on the patio for a party. They'll make you feel like a garden artist right away. If you've been gardening for years, you already know that annuals are hard-working plants; they pump up the garden with color, fill in the inevitable gaps in flower beds and instantly turn flowerpots into movable showpieces.

"Annuals remain wildly popular," says Jeanine Standard, a spokeswoman for Proven Winners, the company that introduced high-performance Supertunias (and many other plants) to the gardening world. "There's no other way to get that amazing impact of color in a landscape," she says.

Pink and purple flowers are a hot trend this year, Standard says, and she thinks it reflects optimism among gardeners: "When people are optimistic, they love brighter colors." Proven Winners' flashy Bubble Gum Supertunia is the company's annual flower of the year, chosen by retailers who vote based on customer preferences. Besides pink, you can find Supertunias in lots of other colors: cherry, rose, raspberry, lemon, white and a rich, velvety purple. They will fill a flowerpot all by themselves, spilling exuberantly over the edges.

Gardeners are looking for more than color, Standard says. They want plants with other purposes, too, and annuals fill an important niche. They attract butterflies and other pollinators, and they can bring hummingbirds to a garden. Standard's favorite hummingbird plants are cupheas and salvias, which she pairs in pots with a Black Cherry Supertunia.

Consumers also want to conserve water and other resources, she says, so plants that don't need pampering are in demand. Hybridizers have responded by introducing ever-tougher annuals, such as lantanas, vincas, euphorbias and verbenas.

When you're buying annuals, a shopping cart gives you a place to try colors out next to one another and experiment with combinations that you can then plant in your pots and flower beds at home. Check the labels on the plants you like: These days, many labels suggest companion plants in complementary harmonious or contrasting colors, or foliage plants to add interesting texture to a combination in a flowerpot.

Don't be afraid to go big. "The one big trend I have been talking about with people is toward large, statuesque annuals, versatile enough for sun or shade," says Bill Calkins, product marketing manager for Ball Horticultural, which introduced ever-blooming, heat-tolerant Wave petunias, among many other annuals, including zinnias, begonias, lantanas, verbenas, impatiens and coleus. Calkins says customers like large annuals "because they look big and tough -- and they are; they're rock-solid."

These days, gardeners are making adventurous combinations in pots, Calkins says, starting with tropical plants for drama and filling in with colorful annual flowers and foliage plants of every description. The palette and performance of coleus plants, which are grown for their splashy, flashy foliage rather than for their flowers, are better than ever, he says, and many coleus work well in sun or shade.

New, compact, long-blooming zinnias, marigolds and torenias are showy plants that mix well with others in containers or look great on their own. Profusion and Zahara zinnias are fresh, bright and tough as nails. "We have zinnias for a reason," Calkins says. "They are awesome. They hold their color and just get more vibrant through the season."

Calkins, an avid gardener, also loves growing vegetables in pots. Both ornamental and edible peppers, for example, look terrific in containers. Arugula and greens of all kinds add plenty of color and texture to pots. "Gardeners are having fun with edibles," Calkins says, and they're doing it in flowerpots. Last year, he combined eggplant, petunias and marigolds in a flowerpot. "It's fun to play around with that stuff," he says.

That's what annuals are all about. Let yourself go with combinations of colors and textures. Plant pots with one flower you really love, or make combinations to suit your taste, to match your house trim or to complement the pillows on your patio furniture. "Nobody wants one-size-fits-all flowerpots," Calkins says. Put annuals to work, and you'll be richly rewarded.

SIDEBAR

Taking care of annuals

-- When shopping for annuals, be sure to read the labels. "Full sun" means at least six hours a day, although eight hours is even better.

-- If you're planting in flowerpots, buy fresh potting soil. Potting soil retains moisture well, and it is lightweight and easy to work with.

-- Pay attention to watering. Plants in pots will absolutely need regular watering. Plants in the ground have access to moisture deep in the soil, but they may need watering in the heat of the season, too. If you're not sure whether your plants need water, poke your finger into the soil. If it feels moist, you can wait a day to water.

-- Annuals need nutrients to bloom all summer long. Add a slow-release fertilizer when you plant, and supplement it by watering occasionally with a water-soluble fertilizer -- you can mix it in a watering can.

-- To keep annuals looking fresh and tidy, you may want to clip off flowers as they fade. This also encourages the plants to keep producing more blooms.

Window boxes are charming miniature gardens with all the same horticultural potential of a big flowerbed in the ground. Because the scale is limited, you'll need to concentrate on smaller plants, but you don't have to compromise on style.

When you're planning a window box -- or a series of them for the front of a house, a balcony railing or a terrace wall -- think creatively. You could fill a box with bright red geraniums, of course, but this is a fine opportunity to explore other options at little cost. Succulents, ornamental grasses, perennial plants and small shrubs are all great candidates for window boxes. Tropical plants, such as caladiums, small palms or bromeliads, are excellent choices, too. They will flourish through a long, hot summer without pampering.

But your first choice has to be about the box itself. Garden shops and big-box stores sell window boxes in standard sizes to fit most windowsills. Hayrack-style planters, lined with coco-fiber inserts that hold the soil in place, are also widely available. If you can't find a planter that quite fits your situation and suits your style, easy do-it-yourself plans, adaptable to windows of every size, are available on the internet.

There's no need to splurge on an elaborate container: Simple boxes may be best because the plants are the real stars of a window box. You may need to install brackets (available at garden shops and building-supply shops) to support the container. Whatever container you choose, it should have drainage holes.

Before you shop for plants, consider the conditions where your window box will be mounted. You'll need sun-loving plants for south-facing windows, and plants that flourish in shade for windows facing north. Most plants will thrive in spots that receive good morning (eastern) light. Afternoon (western) exposures can be a little hot and harsh, so if your windows face west, look for plants that can take the heat.

Your own garden can be the inspiration for window box plantings. Ideas that work in the ground will usually work well in planters, too, on a smaller scale. Go ahead and try your favorite plants in your window boxes -- there's nothing wrong with more of a good thing. You may want to echo the colors and textures in your garden, or complement them with different tones and shapes.

At your local garden shop, remember to think about all the options. Many people tend to rely on annual flowers for window boxes, but shrubs and perennial plants will make a window box planting more interesting than an all-annual design. They broaden your palette. Small shrubs, such as boxwoods or dwarf conifers, will give your window box garden a fine foundation. Take a look at miniature roses and even small hydrangeas. Plants in one-gallon pots might be just right: You want plants that are large enough to show up right away and get your little garden in the window off to a strong start.

Low-growing ornamental grasses, such as Mexican feather grass (Stipa tenuissima), dwarf Japanese bloodgrass, short fescues or little fountain grasses, which have bottlebrush-like blooms, will fill in around flowers. Hostas, especially those with a creamy stripe or other variegation, will look far more distinguished in a shady exposure than a window box full of the usual impatiens. Try combining coral bells, hellebores, salvias or succulents with window box favorites, such as begonias and ferns.

Trailing plants will add to the fullness of your design, but choose carefully. Ornamental sweet-potato vines will require regular trimming through the summer. Cascading petunias or million bells (Calibrachoa), which has many small flowers that look like petunias, might be a better choice. Bacopa, lobelia and even ivy all trail gracefully.

Just like a garden in the ground, your window box can change through the seasons. You might start the spring with a few daffodils and tulips from a garden shop, then replace them with sunny annual flowers or herbs after the weather warms up and the bulb flowers fade. In midsummer, you can brighten up the palette with new blooms; and in fall, you could find a spot in your window box for mums and asters, or add edibles such as Swiss chard, mustard and kale. Don't worry about disturbing existing plants; everything will settle down as soon as you water. On the other hand, if a plant is getting tired, get rid of it -- and the sooner, the better.

Window boxes are the perfect size for new gardeners who are not yet quite ready to commit themselves to a big undertaking. They're also a great way for experienced gardeners to try out new ideas. For renters, they are an easy and obvious choice. You don't even need a window: boxes fit on a balcony or deck rail, and they're pretty on a porch or patio. And now is the time to plant them, for a miniature garden you'll be able to enjoy all season.

A big garden is a delight until -- suddenly or gradually -- it's not. All those magnificent flower beds, the great, sweeping green lawn and your own personal arboretum might become more of a burden than a benefit when the kids are grown and gone and you're ready to pack your bags and see the world. You still want to stop and smell the roses, all right, but perhaps just one rose bush is all you need.

Downsizing in the garden doesn't have to be demoralizing.

"It's interesting. For me, it's good. I can be creative with that," says Kristopher Dabner, owner of The Greensman garden design business in Kansas City. Dabner often works with longtime clients to redefine their gardens after years of residence in one house. He helps other clients who have moved from a large property make the transition, gracefully and happily, to a smaller space. Yes, you can take your grandmother's peony plant with you, he tells them, but "think of this as a new opportunity to be creative, and to think about your garden in a different light."

Distilling the beauty of a big garden down into a more compact frame can be exciting and invigorating. It might involve putting smaller spaces to work for more than one purpose, and drawing on your experience with a large garden to choose the plants that look great through all four seasons, Dabner suggests. Shrubs that bloom in spring, produce bright berries that attract birds through the summer, take on brilliant autumn colors, and have interesting structure that reveals itself in the winter, more than earn their keep in a garden, he says.

A smaller but no less beautiful garden will call for a choice selection of smaller trees and shrubs. Dwarf conifers and small shrubs may need a little pruning from time to time to keep them trim and tidy, but "they don't need hacking back," Dabner says. Instead of a full-sized ginkgo tree -- a great pleasure in a big garden -- plant a dwarf ginkgo, he says, "and you can have the great texture and glorious fall color on a scale that works with the scale of your garden."

Mary Palmer Dargan, of Dargan Landscape Architects in Cashiers, North Carolina, also takes a special interest in downsizing for clients who no longer have the time, budget or desire to work with big garden spaces. Baby boomers are moving in this direction, she says. Often, downsizing is precipitated by a life-changing event: The kids move away, a spouse dies or you buy a summer home halfway across the country. Older clients may not be as agile as they once were, "and there are hazards you didn't even think of," she says, such as negotiating a winding path of rough-cut fieldstones or climbing up and down steps between two garden levels.

Dargan helped her mother reinterpret her garden when "she didn't need all those garden rooms" anymore and no longer needed a big, flat lawn for parties under a tent. You don't have to move to make the transition to a smaller space, Dargan says: Just change your focus. Make the most of the back porch; add on a pretty terrace or a courtyard. Replace flowerbeds, which need and deserve a lot of attention, with fine shrubs. Add lighting so you can enjoy your garden late in the evening without venturing out. If possible, let garden-maintenance companies handle the mowing.

Clients who shrink their gardens, either by moving or by redefining what they already have, often don't want to give up entertaining outdoors, and they don't have to. "Socializing is important," Dargan says, but maybe you don't need a great big picnic table any more. Scale it all down.

Garden art and fountains are high on the list of handsome and undemanding garden features clients want in their smaller-scale gardens, Dargan says. Indulge yourself, she tells them. "This is the last time they are going to do it, and they really want something of lasting value, something that resonates with their heart."

No matter what your circumstances or situation, the best way to get started downsizing is to start with some judicious editing, Dargan says. Simplify your flowerbeds. Limit your collections. Take advantage of a lifetime of experience. Concentrate on plants that do not need pampering, and plant them in generous sweeps and repeating patterns throughout your garden. Changes like these will make your garden simpler to care for.

Good design, careful decisions and pinpoint focus make the transition exciting. "Clients tell me, 'I love my garden so much more now,'" Dabner says. Smaller gardens really are not a compromise: There's still plenty of room for charm.

SOURCES

-- Kristopher Dabner, The Greensman, thegreensman.com

-- Mary Palmer Dargan, Dargan Landscape Architects, dargan.com