In the landscape, red foliage can be a valuable tool. Picture, for example, a brilliant red maple at the corner of a white stucco house. The soft, rich tones of the foliage would provide a warm contrast to the starkness of the paint. A purple-leaved plum separating a Colorado blue spruce and an emerald-green pine helps to resolve their discordant hues.
A garden enveloped in a seemingly endless sea of green privet hedges could work well with the addition of a grand tricolor beech or a clump of smoketrees for contrast.
An unusual way to roll out the red carpet outside the house is to spread the ground with variegated ajuga. Over the years the pinky tones may deepen to a rich maroon, a shade probably better suited to carpeting anyway.
I've combined such ajuga in my garden with solid green liriope and bordered the area with variegated hostas. The arrangement has lasting appeal, the ajuga forming a rich dense mat that sets off the taller foliage of its companions, while at the same time accentuating their contrasts in shape, texture, and growth habit.
I also like variegated ajuga as underplanting for delicate variegated shrubs like Leucothoe Girard's Rainbow, whose emerging bright red shoots turn pink, then a combination of cream and white tinged with copper.
And yet, red and variegated-leaved plants don't always make the most blissful of mates. With yellow, for example, it all depends on how bright and splashy the yellow is, since yellow, like red, is a means of creating accent or contrast -- and if used close together the hues could overwhelm each other.
A newcomer to the class of red-leaved plants is the redbud, Cercis canadensis Forest Pansy, a handsome medium-size tree whose scarlet-purple leaves mature to maroon. By siting the tree in order to allow sunlight to pass through the new foliage, a brilliant scarlet effect is created.
Nature presses red foliage into service for other reasons. Mel Tessene, a botanist who is vice-president of Harris Moran Seed Company in Rochester, N.Y., says red is the covering that protects a plant from getting sunburned, shielding it from ultraviolet rays. That's why the tender new growth of some leaves that later turn green emerge tinged with red. The hue serves as a sun screen.
While red foliage withstands high light intensity better than the green types, it heats up more quickly, Mr. Tessene says. Thus red-leaved plants such as maple and plum need a greater supply of water.
The quality of red is also a barometer of health. If red flowers or foliage lack vibrancy, it may indicate nitrogen deficiency, Tessene says.
Foliage is more important to a plant than flowers; therefore, flowers will be sacrificed to preserve the leaves. A plant will break down red pigment to get at the nitrogen.
Tessene adds that insects are colorblind to red, seeing the hue as black. Insects, therefore, are not the pollinators of naturally red flowers (as opposed to hybridized red). That responsibility is assumed by the birds.