Two colors if fine if that is what you like. It's about what you LIKE. I will say that too much purple in a shadier location will not always show up really well, especially if you like dark colors. However, you can certainly pull it off if you check to see where in your area plants with white or ivory flowers (or even variegated foliage) bloom with some purple plants. Place white behind the purple to show up the purple on a beautiful light background. That way the purple doesn't fade into the shadows.
In the same way you are using two hue's of white (white and ivory) you could use various shades of purple- some brighter and some darker if you like that look.
You mention your fear of white and purple alone being too "busy". Use your foliage to make sure it's not! Create areas of green as places for the eye to rest. Nice larger leaves like large hostas are often used for this purpose and make a lovely resting place between flowers, for the eye in shadier gardens.

I think two-color themed gardens can be very relaxing to look at. ggg has mentioned some good points tho.

I have a sunny bed in purple (blue-violet to red-violet) combined with cream-palest yellow flowers. Salvias--cardonna, purple rain, yarrows-- pale yellow and cream, beauty berry bush in the fall, Edging with cream and purple hyacinths in early spring and annual salvias in jewel town purples in the summer. It's an island bed viewed from all sides. Purple Emperor sedum. I love it. I have some large alliums and a yucca near the center for height. It's
quite dry. Yours sounds as if it might be damper.

Your choices sound very nice and will probably do
well with light shade as well. I think the colors
are wonderful together.

Yep I agree! The colors will look so pretty and most important your garden should make you happy! I know mine does.

Well, my house is white with pale-gray Carthage stone. This bed will be right in front of my front porch which has a white railing. I thought the purple flowers or some dark purple foliage would contrast nicely with it. It's not TOO shady, just in the afternoon when the shadow from the house hits it. I think there is enough sun for most things to grow well, but not enough to scorch it and not enough for plants that want full sun. We usually get plenty of rainfall here so I'm not worried about dryness. I have quite a few more ideas of things to add. I was just hoping that two colors wouldn't look confusing to the eye or look boring. I guess if others have had success with it then it works, so I will try it! Thanks!

I have quite a bit of work to do, but I'm really looking forward to sitting on my front porch with a glass of iced tea and looking at my flowers!

Depending on where you live, your afternoon shade is probably BETTER than full sun (it surely is in my garden!). And how lovely you have one of those beautiful stone homes. Is it a heritage home? I think your garden is going to look absolutely beautiful. If it is right in front of your porch, you may want to include a little bit of winter interest if you come and go out that door. I have some beds without "foundation" plants by my porch and front door...they are so NEKKID during winter. Someday there will be some other things in them but the jasmine vine and some containers help for now...

Heritage? I doubt it. It was built in the 1950's, which is old but not THAT old. I think whoever built it just wanted some fancy-looking stonework to offset the siding. As for some foundation, I'm thinking of putting a shrub or two in there along with maybe a birdhouse-on-a-stick (or pole, I guess). I wanted a butterfly house but I can't find one I like that isn't ridiculously expensive.
I'm also thinking about a birdbath in front with a flowerbed around it, a bulb garden along the curb in a nice sunny spot, and a shade garden under my large maple tree, but those are projects for another time. My yard is so bare! But I can't do it all at once!

Sounds like a great plan. I am considering a light blue and purple bed, just those two colors. I love that combo, and the rest of my garden is all in hot colors.

You may want to try some bearded irises, since they come in purple and white and some even have variegated foliage. Siberian irises are gorgeous too and have pretty foliage.

One bed at a time...

Renee

I love tall bearded iris but I figured they would want more sun than that front bed has to offer. I have other areas that are more sunny for them. The purple and light blue combo sounds wonderful. Do you plan yours for color only or do you consider things like fragrance and attracting butterflies? I'm considering a couple of things for the smell and for the hummingbirds and butterflies, but those are bonus traits. The main thing right now is that they will be fairly easy to get established in that spot.

I have black snakeroot from Bluestone growing in my full shade bed north side of my garage. The toad lily growing beside it started blooming late summer and kept going until the snakeroot bloomed in late October. This is another purple/white combination you might consider for late/end-of-season interest:

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Oh, I love any garden that has purple, lavender, or both :)

Your garden sounds like a great idea! Some purple hostas would do well (they're very pretty) and maybe some white bleeding heart? Lily of the valley (just remember it's poisonous) and violets are wonderful, in front. Some sweet peas (they have all lavender, purple or white) would be beautiful. They need some sun in the spring, but would prefer a little shade for summer, so if you have big trees leafing out, that should work.

Also a great choice, little violas and pansies, maybe some purrple and white columbine...and if you have a little sun in front...purple, lavender and white alyssum are beautiful and have such a nice fragrance! If there's a little sun here and there, purple, lavender and white stock are all beautiful. I planted dark purple hyacinths all along the front of my garden and the bumblebees love them!

I think a birdbath is a very nice idea. Adding some plants for the bees, butterflies and birds is always so much more enjoyable...and brings life to your garden. Catmint and lavender are also great, if you have a sunny edge.

My gardens are usually pink, lavender, purple and white, with a little blue...although I do have much sunnier colors in the kitchen garden (with the vegetables, fruit and herbs). Enjoy your new garden! Here's a picture of my front bed, with the bird bath. The roses are still small, but you can see the lavender and the alyssum :)

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Here's a close up of the pansies, in the fairy garden. This is on the shady side of the house (northeast) but the pansies love it! I think the white is verbena.

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gardenweed,
Do you find that the snakeroot and toad lily require a lot of water? They are so pretty but I'm not sure if I'd be able to hydrate them enough...

lavender lass,
Which species of pansy is that? So pretty!

rocking zappy,
I think that's a great color combo, and you can incorporate different colored and variegated foliage to add more interest. Lime-green foliage looks very nice with purple flowers--pineapple upside-down cake hosta or japanese forest grass would pair well. Siberian iris need less light than bearded iris and do well on the northeast corner of my home (and they come in purple, white, and blue--white swan is my favorite). If you wanted to stretch the purple into a more magenta color, Foxy foxglove is beautiful, a manageable height, and easy to grow (but like all foxgloves very toxic, so not good for dogs or kids) and Pam's Choice foxglove is a beautiful white with a maroon throat.

newbie - the snakeroot and toad lily did as well as any of the others in that bed with the terrible drought we had last year. I watered everything, every day, hoping I wouldn't lose anything. I'm pretty sure most everything will come back. That was only the snakeroot's second year growing there and it was the first year for the toad lily so I can't be sure how they'll handle "normal" growing conditions in that bed. It IS a dry shade area but everything else thrives during a year with normal rainfall.