I think the main thing to beware of is putting warms & cools together (lavender pinks next to peach pinks, burgundy next to bright orange).

Tomato-ish red roses are just too bright for me;
I gave away Red Ribbons, a really nice & easy rose, because I couldn't see anything else in the garden when it was there.

I think red is a powerful "punch" in the garden, & it looks really good if it's saturated & if it's big enough to make an impact but not so big that it overwhelms everything else.

In some things I like opposites & contrasts:

bright yellow with blue or purple (Stella de Oro, coreopsis, or Partridge Pea with Salvia Black & Blue or with dark purple morning glory)

red with white or silver/green (any deep red flower against white crepe myrtles or dusty miller/artemesia or culinary sage)

burgundy with greenish white (Tradescant with culinary sage or wandering Jew)

In other things, I like harmony:

peachy colors with warm pinks (Abraham Darby with peachy daylilies)

shades of coral (coral honeysuckle with canna indica indian shot in the coral color)

red with red (Dynamite crepe myrtle surrounded by Red Cascade roses).

& even though I don't think of myself as a "pink" person, & even though I think Knock-Out roses are over-exposed...

A co-worker just bought a house with a big square bed at the front corner.
The bed has a big pink crepe myrtle in the center with pink Knock-Outs surrounding it.
beautiful!

I am a fairly conventional person, and my chief drawback is looking at each plant individually rather than at a group of plants together. So I mostly go for very conventional combinations (pink-purple, yellow-purple,etc). My husband, on the other hand, is a talented painter (of pictures, not houses) in his time away from the office, so he does come up with some unusual ideas. His color schemes do go wrong occasionally:-) and then he is punished by having to dig things out and move them around in winter, but mostly they do work. For example, he thought we should plant Carding Mill and Eugene de Beauharnais together, a combination I would never have thought about on my own. I have posted some pictures on the gallery.

Masha

Here is a link that might be useful: Rose and Companion Combos

I really like pastels with pops of intense color (only selected pops)

example,... Madame Alfred Carriere and Jude the Obscure are pale and soothing. They look delicate and romantic to me. I love the slight fading of color into another, nothing too brash, just a subtle fading.

Near those, I like hot pink like La Reine and bright blue/lavender (lavender itself or geranniums or something).
My actual favorite color is blue (on the purple side of blue). I naturally feel very happy, peaceful and just well, PLEASED when I see this color. It looks like a gemstone or the ocean to me.
Pink is my next favorite color. :) Hot pink feels very appealing and candy-like to me,... and perhaps a bit lush.

I can appreciate all colors in different uses and combinations, but, in a garden, these are the colors that repeatedly make me happy. In my clothing and in other parts of life, I love bright red,... but I don't tend to like it in my garden.

I pretty much never like orange unless it's a blended orange/yellow like Alchemist.

I don't like bright color blends like Double Delight.

I know plenty of people who just pick all the roses they like and grow them together regardless of color, and there's nothing wrong with that. It pleases them and makes them happy. But I mostly prefer pastels with a few pops of bright colors like little jewels sitting in a pile of lace.

but we'll see whether I really chose colors that would look good together, hopefully, next year, when my roses actually start to have more blooms at the same time. though maybe I'll have to wait another year entirely. :)

What I like to do is open up separate windows with a representative photo of each plant and rose and sit them all together on my computer desktop to imagine how the colors look together. Or I'll open up a drawing computer program and do dabs of those colors by each other and see how they make me feel.

I basically like color combos like what Masha has going on in her garden: :) :)
http://i655.photobucket.com/albums/uu274/mashamcl/companions/53d1b0fd.jpg
lavender companion plants,... pink, hot pink and pale yellow or off-white.

I have Jude the Obscure right by William Shakespeare 2000. It makes me very happy.

I once experimented with a bed of dark red fragrant HTs. Oh, my.

I kept one, Oklahoma. At least now I know which is my favorite rose of this description.

;->

Rosefolly

Well, Suzy, you just blew my plan out of the water. I was going to place Duquesa next to Hermosa because I want excellent foliage there but failing to consider the resulting clash since D is peachy and H is lavendery. So Bowbells, a purer pink, I believe, will go next to Hermosa, and I sure hope B is nice and bushy. D will go over next to SdlM and Enchantress. From the looks of Masha's pics peachy ought to be peachy next to magenta.

Sherry

Sherrrrrryyyyy get Bow Bells, it's SO PRETTY. I keep almost buying it. Everytime I see it in person I fall in love with it.

I have lots of rules but find them hard to put into words. I agree with your original comment, Suzy, that matching colors that are close is peculiarly taxing. I think I would get along with Masha's husband, as I also place vinous reds with pale warm colors. I don't like too many pale or too many powerful colors together: one is anemic; the other too heavy or too leaden. Like Aimeekitty I like little dashes or flecks of strong color in the middle of softer tones: wild poppies self-seeding in the garden are perfect, and surprisingly, their brilliant orange-red goes with nearly everything. White is not a universal peacemaker, but a color like any other. I don't like pure white, just as I dislike primary colors in the garden in general, finding them impossible to harmonize; but I like whites that are are tinted with parchment or honey or cream or lemon. The leap from white to strong colors is too great a one for me: I avoid white beside red, for example (though I will consider purple roses and white ones side by side). I dislike colors that I consider hard--certain shades of brown-tinted orange-red would fall in the category, also the primary colors--but otherwise like just about everything and think it can be used to good effect, whether rich and somber, or pale and soft, or brilliant and flashy. The art lies in putting the right colors together and in the correct proportions.
Of course I like lots of soft blues and violets and lavenders in the garden: a rose that can't get along with them is hardly a rose at all; and I appreciated purple foliaged plants with roses as well, especially cool pink roses and red ones. Gray-green and steely and silvery foliage is also excellent with many roses, though that hardly needs to be said. And let me put in a word for acid and yellowy greens. A lot of times I just don't know what will work, and I'll take bits of two plants if I can and place them side by side. With babies or plants I've never seen in flower, or that aren't in flower when I need to plant them, I just do my best, which sometimes isn't good enough so that I end up moving things. Just throwing things together doesn't work for me: some combinations make me flinch, while others are joyful and exquisite, so that I have to think out colors. Verbal rules for color matching are almost always inadequate; I suppose a fine set of charts and knowing how to use them would get the color designer a long way.
I love talking about color, Suzy, thanks for bringing the topic up.
Melissa

I mostly like deep colors - dark violet, velvety red, deep orange, deep blue, mossy green and so on. Pink is somewhat deep down my priority list, I like salmony pink, but not that fond of baby pink or magenta pink - what is a bit of a problem when roses are the best growing flower shrub here. :D I grow quite a few pink roses, but I mix them with blue, white, red, peach, even light yellow. Then I have my yellow - orange corner, where I avoid pink all together and use only yellow, orange, blue/violet and white.

If I get to making a bed for it this autumn, I also plan on a crazy colors corner. I have a few roses which color can be described that way, Suntan, Euphoria, Wonderland, Bonita - add kniphofia to it, some fucsias, some bat flowers (Cuphea llavea) and some other tropical craziness - should be fun in the middle of vegetable garden. :D

What I do hate though are roses that fade from orange to pink - can't stand it! Also, with other plants I hate that made-out-of-paper look like some oriental lilies or large flowering clematis can have.

Sometimes I think I'm like one of those artists that throw paint at the canvas. That can be a problem when you hate moving roses. There are several garden areas that work really well for me. One is all purples and gold with a few spots of red. It feels charming and childlike. Another garden is all yellows and white. It's pleasing and not boring to me. I have two beds planted entirely to red roses. I am particularly pleased with the shade garden with all its many shades of green and red leaves enlivened by hydrangeas and cool colored lillies.

I have the added problem, if one can call it such, of trying to integrate the garden into the wild, hilly landscape that surrounds it. I personally can't abide bright reds, oranges or garishly two toned roses like Double Delight, and the landscape seems very accepting of creamy white, purple, pinks on the lavender side and soft yellows. Adding companion plants is an absolute requirement and there again I stay away from garish colors that would clash with the subtle tones of the wild plants. Green is a great unifier, as are the silvery plants such as butterfly bush, and cypresses which give such a sense of place here and can be seen in other gardens in my area. A more subtle color palette works well here, although one can be more adventurous closer to the house, such as the glorious deep pink of Yves Piaget which later turns to a beautiful silvery pink. The apricot of Carding Mill overlooking a dry hillside was not a success and has been moved. The silvery pink of Le Vesuve there, however, looks perfectly at home. Your surroundings will very often tell you what they want, and I've found I do best if I pay attention and respect that.

Ingrid

I'm pretty much a "pure" colors guy; bright reds, clear pinks, sunny yellows, etc. My garden contrasts a lot, not so much complements. I don't often think of what flowers I'm putting next to each other so I sometimes get really crappy combos, but I'm much better making sure the foliage works together.

Agree with Campanula; the pinks are the hardest to get right and combine. So, for instance, my bluish-pink David Thompson next to Carefree Beauty has never worked well for me...but if I get up the energy, I'll just scratch the David Thompson...I don't like the color alone either!

Here is a link that might be useful: Garden Musings

The colors will vary seasonally as well as regionally.
The deep pink you so admired in a friend's garden late last October may disspoint when it's in full sun in your yard in late June and the pink just won't hold in the sun.

And then there's English Elegance which seldom matched the colors in DA's first book until I gave it an overwinter dose of woods ash.

So many variables.

Bright orange crocosomia near a burgandy japanese maple surprised me by its loveliness.

I'm getting tired of pink.

I like white anything but only if they don't turn to dirty tissue and demand to be deadheaded.

How many shades of purple are there, exactly?

I like all colours, including yellow which seems to be most people's pet hate among colours. But what would spring and fall be without yellow? The pale northern light is a problem for me, strong colours don't work well here. I've kept the reds, oranges and yellows in my sunset garden to the west of the house. Just now it is bright with rudbeckia Goldsturm and another rudbeckia with bigger flowers, goldenrod, an orange crocosmia, ligularia Desdemona, the roses Sutter's Gold and Brown Velvet and several heucheras, Palace Purple and Caramel. There is more red in high summer, yellow again in spring.

The rest of the garden is rather bland by comparison. Most of my roses are OGR's in various shades of cool pink, dark rose and purple with companion plants in silver, pale yellow, blue, lilac, purple and maroon. I really like pale yellow with darkest burgundy red, for instance perennial foxgloves with Greek scabious.

I have several shade borders in green, white and palest yellow. I don't know what else I could do with these borders under pines and junipers. Not even blue works in the dark. I have black with white in sunnier positions.

Wherever there is a risk for a colour clash I add alchemillas, my safe guard.

I love blue-purples of the periwinkle persuasion like aster 'Monch' or agastache 'Blue Fortune' and phlox 'Franz Schubert' next to gold-yellows or butter yellow flowers like deamii black-eyed susan, heliopsis and coreopsis or perennial sunflowers. I would imagine yellow-apricot roses would look stunning next to them as well, like Crepuscule or Safrano. You can do this similar colors with clematis, Crepuscule and Veilchenblau or a blue clematis.