Answer: I've seen several theme gardens, and one contained only plants with red, purple or bronze colored leaves. It was quite striking. There are two references that will help you compile a list of plants which will grow well in your gardening zone: Right Plant, Right Place by Nicola Ferguson, published by Summit Books, ISBN #0-671-52396-1, and Taylor's Guide to Garden Design, published by Houghton Mifflin Company, ISBN #0-395-46784-5. Both books have listings of red only foliage, among other themes.
Hope the above helps. You might try to visit Brooklyn Botanic Gardens for a few ideas about theme gardens.
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