Red adds excitement to garden but comes with challenges

All reds aren't just red. Whole books have been written on the use of color in garden design, but even a brief discussion of color in general and red in particular will go a long way toward a harmonious design.

Colors on a design wheel are arranged in a progression according to their relationship to each other. Reds run from violet-red to pure red to orange-red. From there, the hues circle around from orange to yellow-orange to yellow and so on, eventually back to violet, in the same order as they appear in a rainbow.

Reds can be considered hot, warm or cool. If you look at a rainbow or an artist's color wheel, you'll see that there is a band of reds that stretch from purple to orange. In the very center is pure red. As you move toward orange, those reds have a degree of yellow in them, and as you move back toward purple, the reds have a degree of blue in them.

Reds that are closest to the orange end of the spectrum are considered hot reds and look orangy due to the yellow they contain. Warm red is a pure red with no added hues, dead center on the red band. Lastly, reds on the purple end have some blue in them and are considered to be cool reds.

All reds are not equal, nor are they necessarily compatible. Reds can clash in the landscape. Bright warm reds do not mesh well with bright cool reds. For example, peony Coral Charm is warm and does not mix well with peony Scarlet O'Hara which is cool.

Hot reds and oranges are good with cool blues, green-blues and blue-violet. Warm red works best with oranges, yellow-oranges and yellows. The cool reds such as magenta, crimson or bluish-pink are best complemented by lavender, blue and red-violet.

Also consider the background against which flowers will be seen. Brick walls can vary from orangey-red or buffy tan to dark red and those colors will be part of the overall design.

To plant a monochromatic red garden that uses no other colors pay close attention to whether the plants you are considering have cool or warm hues. Stick to all of one or the other so your garden is either all cool reds or all warm reds. Add interest by selecting a variety of shapes and sizes as well as lighter or darker versions of your main red.

Look closely in your garden and you'll see that red is everywhere. Newly emerging foliage often has tinges of red to it. Many plant stems and leaf petioles are reddish. Summer leaves can have varying hints of red in them. Most notable are the obvious reds of flowers and fall leaves, and the welcome reds of crabapple fruit or dogwood twigs in winter.

Bright pure red carries a lot of weight and is easily overdone. Public gardens often use huge swathes of annual red salvia. While this can be appropriate in a large public setting, it generally isn't ideal in the home landscape. It's easily overused in a small-scale setting, creating a jarring display that quickly tires the eye.

If a small amount of pure red goes a long way, then how much red is enough? That depends somewhat on the size of the planting bed and how far away from the average viewer it's located. For the truly precise gardener, a ratio can be used to determine what proportion of red on average is needed to balance other colors in the design. For example, in a yellow-green and red-violet design, a proportion of 40 percent yellow-green to 60 percent red-violet is recommended for good balance.

Alchemilla mollies is the perfect yellow-green foil for all reds. Its soft yellow-green leaves fill out early and last until frost, catching drops of rain and dew. In early summer, airy yellow flowers rise above the rounded, scalloped foliage.

Dark red and dark red-violet plants provide subtle interest in the landscape, behaving almost like a cool color. Maxilla perilla and Royal Purple smoke tree are two good examples of red-violet plants that lend a soothing element in the garden.

Red flowers are often sun-lovers but shade gardens have their fair share of great red plants, too. Final red astilbe and Kong coleus are excellent planted among hostas or ferns. The arrow-shaped leaves of Caladium can have bold splashes of red. Caladium is a good plant for tropical ambience in the garden. Red Angel Wing begonia adds drama.

Wax begonias, red coleus and red impatiens are the good old reliables of the shade garden.

Red is the most exciting and challenging of colors to use in garden design. Have fun with it but remember: a little bit can go a long way.

•Beth Gollan is a horticulturist affiliated with The Planter's Palette, 28W571 Roosevelt Road, Winfield. Call (630) 293-1040 or visit planterspalette.com.