All white gardens can be beautiful, and you're right you have to take extra care with the shades of green and leaf texture when there are no or few flowers.
Right now my backyard hillside garden is a sea of white. The dogwoods, Viburmun and Fothergilla are all blooming. I also have a various silver foliage out there-Buddlea, Artimisia, Lavender, various sedum and cottom lavender.
Within the next couple of months there will be a riot of color out there, mostly yellows, blue/purple and reds with the occasional splash of orange.
I think if I limited myself to an all season white garden I'd get bored with it.

Have you googled Sissinghurst?

I love all white gardens! There's something so calming about them and I love the effect at night.

I'm including a picture of my still in progress amateur all white garden. My zone is different to yours, but I'll detail what I have:

shrubs: variegated pittosporum (green w/ white) & small leaf holly (dark green)

*soon to be planted in middle zone (not in pic): 6 white lily-of-the-nile

front low plants: aztec grass (variegated liriope) & white wax begonias (foliage is dark green with a tinge of burgandy)

I also have:

2 ponytail palms (all green foliage only) in earth-tone planters with dragon designs

"French Lace" Floribunda rose in blue planter (I felt this gave a nice contrast to the red door and introduced a bit of color...also gives a "water" feel)...the foliage on the rose has a red tinge on new growth, then goes dark green; flowers are all white.

Confederate jasmine twining up a black iron trellis off to the right (prob can't see in pic). The jasmine has dark green shiny foliage most of the time and then blooms lots of tiny white flowers.

Majesty palm in green-black planter in entranceway (the light green of the majesty palm contrasts nicely with the green-black...it's an overall grounding effect for the entranceway).

I also have plans to grow tuberose off to the left of the pic.

For my own design, I struggled with the shades of green. I really prefer a deep dark green in a white garden, but my garage (to the left) creates a lot of shade and the dark green foliage tends to get lost, so I had to end up with a lot of mid-tone and lighter toned greens.

Something I'm experimenting with now is introducing just a hint of color into the all white...like the blue planter and a bit of burgandy in the foliage. I've seen pictures with hints of pink mixed in with the white and that looks really nice.

The April issue of Fine Gardening has a wonderful article called "Variegated plants create drama", I learned a lot from it. One great tip was that from a distance of 15 feet or more, variegated foliage tends to look simply "light green".

So here's the pic - lots of the " white" is not currently blooming or too new of a plant to have much impact yet (too small), but it still looks great at night!

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Very nice...but I think a lot of your plants wouldn't make it in zone 5...but I'll go through the list. I like combining the pots in the garden - nice feature.
Thanks for the input!

zamiagarden, just a quick question: what is the pretty tree that is ringed with white flowers? I love it!

rustyshackleford333, what a wonderful idea! I wanted to tell you about an absolutely gorgeous white garden I saw in our old neighborhood. It was very formal and symmetrical, with very elegant plantings, and it absolutely suited the house. If I remember right, there were lots of hydrangeas and ivy, which provided great backdrops for the white flowers. I'm not sure if you were planning a formal or informal garden, but formal sure seemed to work well with white.

Check out "Moon Garden" up top at "Related Forums".

I guess I'm a little lost as to your design question.

To refer to a recent posting in another thread, it would help to know more about the "box" you will be working with to develop this garden. I thought about simply suggesting plants to you from an old thread that I can no longer find on GardenWeb, which for some reason I saved in a Word file. But then, you say that you have researched many plants and that your question has more to do with combining them.

Then it occurred to me that I really have no clue what you want with this garden. Can you tell me what you hope it will achieve? Is it mystery you're after, as someone mentioned above? Is it a sense of clarity, formality? Is this "garden" going to make use of all of your front yard? Or were you thinking of it as an entry way experience that sharpens the poignancy and sweetness of returning home in the evening or walking guests out as they depart?

I'm not sure that these are good questions, but I am pretty sure that without some further clarification I and others will find it hard simply to recommend possible shades of green and sizes of foliage that will help to create the white garden you desire. It would just be a shot in the dark, so to speak.

Wellspring

rustyshakleford333: Right, I imagine many of my plants would not work in your zone...the pittosporums might (such an easy grower!), and hollies probably would (nice fine texture...slow growing for me). The interesting thing I learned as I researched white gardens is that they are rarely simply "pure white" and adding a hint of color here and there can actually enhance them, so I was trying to show that with the pic (my attempt at this theory anyway).

xantippe: The tree is a small southern Live Oak - it's just a few years old and will get huge. They do really well here in NorthEast Florida - it's a great protection tree for hurricanes too. I absolutely adore them.

A little formal (front of the house) but I'm not looking for square corners or neatly trimmed hedges...just the simple, clean look of all green with white blooms. I've included a link with pics of the home if it would help. I'm just looking for a unique mix of greens with some white blooms throughout the season. I'm happy doing my own research and design - just wondering if anyone had experience with this type of garden and could offer any tips or suggestions.

I welcome any thoughts :)

Here is a link that might be useful: Pics of home