From time to time I mention the design industry's color trends for the coming year because it influences the color of flowers and plants that will be available.

One thing I haven't mentioned is my aversion to leaves that aren't green. Of course I love beautiful fall foliage, but during the growing season I think most tree and shrub leaves should be green.

With only a few exceptions, "red-leaved" trees whose leaves are actually closer to a chocolate brown or trees with chartreuse or yellow-green leaves make me uncomfortable. With other gardeners and landscape designers utilizing these plants, I've felt like a quarrelsome curmudgeon. However, I'm not alone.

Andrew Kaufman and Virginia Lohr, Washington State University professors of horticulture, researched general plant color preferences. They asked a small sampling of people to look at one computer-generated tree in 52 different colors and say which ones they liked or didn't. From this, the researchers selected 11 colors to test on a wider sampling. They didn't include colors such as yellow that generally elicited a neutral response.

Twenty-four subjects, ages 20 to 61, were asked to rate the 11 colors. Green trees, regardless of the intensity or hue, brought about positive responses. Red trees also were in the positive range. Purple trees evoked negative and neutral responses. Test subjects responded negatively to orange and brown.

Kaufman and Lohr believe these responses are "related to evolutionary survival theory." I don't know about that -- I just know I don't like brown trees! They plan additional research to see if these preferences are associated with physiological responses such as heart rate.

Professional and amateur landscape designers may want to keep Kaufman and Lohr's research in mind when selecting plants.

At the top of my personal "do not plant" list is purple-leaf plum (Prunus cerasifera). It blooms early in the spring with light pink to white blossoms. It's lovely in bloom, but the rest of the year its "dark purple" to "copper purple" leaves look brown. Add to this the fact that it's a fast-growing, short-lived tree prone to attack from borers and subject to dieback.

It doesn't have blooms in the spring or many pest problems, but I also would not plant a "Crimson King" Norway maple (Acer platanoides "Crimson King"). Descriptions may call the leaves red, purple or crimson purple, but you can't fool me. They're brown.

Another "red" plant I don't like is red barberry (Berberis thunbergii). Depending on the cultivar, the leaves may actually be more red than brown, providing some contrast in the garden. However, it has nasty little thorns. Plus, it catches leaves and blowing debris that must be pulled from the shrub for a well-kept look. Ouch.

The yellow or golden forms of honeylocust (Gleditsia triacanthos) don't elicit as negative of response from me, but they're best used with a backdrop of green. Standing by themselves, they look a bit sick.

Of course, color is a matter of personal aesthetics. Each of us has his or her own preferences -- what are yours?

* Marianne C. Ophardt is a horticulturist for the Washington State University Extension Office in Benton County.