As you plan your annual flower display or if you’re adding a new perennial bed, one option to consider is the powerful visual impact of a single color.

Choosing flowers in only one color may seem monotonous to those who love to combine plants with complementary and contrasting colors. Yet, the bold, beautiful singularity of one color may surprise you.

First decide on a color: You’ll have numerous plant choices in red, pink, purple, yellow and even orange. The nice part of doing this with your annual beds or containers is you can change your color scheme each year.

Cooler colors such as blue, green and violet create a more serene, calming effect, and appear to be more distant. Warmer colors such as red, orange and yellow are vibrant and make a space seem smaller.

You certainly can plant all of one bedding plant, such as geraniums, impatiens, petunias or other popular annual flowers for a unified look.  Or, you can mix and match plants in the same flower color to give you a variety of heights, textures and bloom times. This adds structural interest, depth, variety and ensures flowering through the season – and gives you the pleasure of choosing several plant or seed varieties.

For greatest success, choose plants that prefer similar growing conditions, such as hours of sunlight, soil type and moisture.

You’ll find shopping for a single color streamlines your garden center visits (not that most of us want to rush through these). Be sure to check plant tags for mature heights and widths to ensure variety in your planting. If buying perennials, check also for hardiness to zone 4.

Or, shop ahead by finding lists of flowers by color. Check gardening books, or search the web by color name for scores of ideas. Two great book resources I refer to often are Sunset’s “Annuals and Perennials” and Tracy DiSabato-Aust’s “The Well-Designed Mixed Garden.”  She is a master at compiling detailed lists of perennials by bloom time, flower and fruit colors, foliage, form and other characteristics.

Planting a monochrome perennial bed also offers several advantages, especially if you adore a certain color, want to echo your home or accent color, want to make a small garden seem larger or want to brighten a dark corner.

Choose your color. The options are expansive. With perennials, it’s especially important to choose plants that have varying bloom times. A symphony of pink or purple in June needs an encore performance in July or August and September. Fill in with annual flowers, if needed. In addition to staggered blooms, consider plants with foliage or stems that echo your featured color. Plants that are attractive even when not in bloom are the key to season-long beauty in the landscape.

Let’s explore options for one color – white.

With a rainbow of options, white may not top your list. Because it stands out, white tends to divide a design, rather than partner with other colors. That’s all the more reason white works well by itself. It’s especially useful to brighten a dark corner or bring a distant view closer. Another advantage is the number of white-variegated plant options to choose from. The result is cheery, unified and interesting.

White can appear washed out in full sun, so consider it in filtered or dappled light. I used white perennials on the dark, north side of our garage at a previous home. My choices for shade included:

* Astilbe ‘Snowdrift’ – a summer-blooming, fine textured plant.

* Cimicifuga ramosa – ‘Brunette’ and ‘Hillside Black Beauty’ have dark foliage. All have six-foot candlebra spires of white in mid- to late-summer.

* Goatsbeard – This spring bloomer grows to the size of a small shrub.

* Ground covers – Lamium ‘White Nancy’ has variated foliage; sweet woodruff; and creeping phlox. All bloom in spring.

* Heuchera – Several varieties have purple or veined foliage with tiny white spires. They need part sun.

* Hosta – Numerous varieties have white variegation in the leaves and white flowers.

* Pulmonaria ‘Sissinghurst White’ – This spring bloomer has spotted leaves deer don’t touch.

* Solomon’s seal – Choose solid or variegated leaves. Blooms in spring.

* Tiarella and heucherella – Most have silvery veined leaves and bloom in spring.

* Trillium.

Here are a few white perennials for sun:

* Clematis – several white flowering varieties are available, including a fall bloomer.

* Daffodil – several white varieties are available.

* Grasses – Calamagrostis ‘Overdam’ and Miscanthus sinensis ‘Morning Light’ have variegated leaves.

* Harebell ‘White clips’ – low-growing campanula.

* Iris – Siberian, Germanic or bearded – each has white flowering variations.

* Lily ‘Casa Blanca.’

* Penstemon digitalis ‘Husker Red’ – burgundy foliage, white spires.

* Shasta daisy.

* Sedum ‘Frosty Morn’ – variegated foliage.

* Upright phlox ‘David’ and ‘Pax.’

* Veronica ‘Icicle.’

* Yucca – solid or variegated leaves.

Several perennials better known in other colors also have white selections. Among them are balloon flower, bleeding heart, delphinium, Echinacea coneflower, dianthus, liatris, peony, salvia and turtlehead.

A few white-flowering shrubs will add height and structure: clethra, dogwood, hydrangea, roses and viburnum. ‘Carol Mackie’ daphne has white-variegated foliage.

As you’re planning a monochrome garden – or any design – here’s one note of caution from color expert DiSabato-Aust: Use plants with colored or variegated foliage sparingly, as accents.

“Green is a key color. Use other foliage colors judiciously,” she says.