As gardens, porches and patios are increasingly being viewed as "outdoor rooms," design professionals are playing a bigger role in choosing elements and creating color schemes.

Outdoor color should be as carefully thought-out as indoor color, says Debra Prinzing, a master gardener and author of "The Abundant Garden: A Celebration of Color, Texture and Blooms" (Cold Springs Press, 2005). "Color is the easiest and least expensive way to make a garden pop," she notes.

Pick a palette. Then stick to it. "It takes some restraint," Prinzing says. Choose a monochromatic, analogous or complementary color palette, just as you would indoors, then limit yourself to plants and other elements that fit that palette.

Create a mood. A garden can create a feeling of serenity or one of excitement, depending on how color is used, Prinzing says. For a calming garden, choose flowers and other plants with similar hues, such as soft blues, periwinkles and lavenders. For a high-energy garden, combine high-contrast colors, such as hot pinks, bright oranges and sunny yellows.

Light. The eye sees color in the garden differently depending on the quality of the natural light. In Seattle, where Prinzing lives, the skies are often gray. Bright colors in the garden can offset that and work beautifully against a gray canvas. In the Southwest desert, the intense light can obliterate color, making shapes much more important because many plants appear as silhouettes. Designers can make the most of natural light by positioning garden structures, such as lattice and arbors, so the sun casts intriguing shadows.

Focal points. A landscape needs them just as a room does, whether it's a lake view, a specimen tree or a piece of sculpture. Color can create a focal point. One garden in Prinzing's book featured a pair of Adirondack chairs, painted hot pink, as a beckoning destination. "You need something to draw the eye and lead people through the space."

Foliage. Leaves last longer than flowers, many of which bloom for only a few weeks. But with foliage plants available in deep purples, silvers and golds, you won't miss the flowers. Also look for variegated (green-and-white-leaved) plants. "Every popular plant is available in a variegated cultivar," Prinzing notes.

Exercise your green thumb. You don't have to know a thing about horticulture to create a container garden, Prinzing says. Designers know how to use cut flowers to create an arrangement, and they can use that same expertise to create beautiful pots. Don't worry about mixing sun and shade plants, or about spacing, she says. "Containers are so forgiving."

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