This is a difficult topic for many gardeners - everyone wants a garden that looks good 365 days a year. My first piece of advice would be not to demand/expect a garden that "is at its best throughout the year". Even in our very mild climate, the garden will be very seasonal - what looks great in midsummer is unlikely to look quite so great in February. If you design with that in mind, you can achieve a garden that has year round appeal.

My second piece of advice would be to focus on foliage effect rather than flowers. Foliage has a much longer presence in the garden than do very transitory flowers. And flowering is dependent on weather and light factors, vigor of the plant, time of year, length of establishment, etc. while foliage is just.....there :-) Evergreen foliage in particular. This certainly does not mean your garden will be just green or devoid of other color - foliage comes in such a widy variety of colors and color combinations these days that even if nothing flowered you would still be greeted by color and in many cases, year round color.

I would also suggest you look into plants that offer specific winter interest, whether through bark effect (i.e., redtwig dogwoods, stewartia, arbutus), berries, seasonal flowering (Camellia sasanqua, mahonia, winter blooming heaths and heathers) or seasonal foliage color.

And there are various books that address these issues - look for Ann Lovejoy's The Year in Bloom, Christopher Lloyd's The Gardening Year, Sunset's Successful Gardening Month by Month, and Dan Hinkley's Winter Ornamentals and probably many others you will find in book stores and the library.

If you get the right combination of evergreen presence, foliage attraction, winter interest and appropriate seasonal flower color, you will have a garden that will look great throughout the year. How one gets that "right combination" is a mixture of luck, plant knowledge, design skills and research. It's not exactly a paint-by-numbers process. Personally, I find the process to be rather endless, so don't necessarily look for a finished product - garden evolution is a constant :-))

If you have a small garden and are trying to get the most amount of flowers for a long period of time I have a few tips. Plant lots of bulbs. You can have spring bulbs blooming from Feb.-May and when they go dormant the other perennials that you plant come up and take their place. You can plant spring bulbs with perennials that come up in April or May. Daylilies, asters, coneflowers and other summer blooming perennials go well with bulbs planted in a sunny area. If you have a shady area you can plant arums,cyclamen, and ficaria under hostas and late emerging ferns. They bloom and grow from September through May and then go dormant when your hostas and ferns emerge. If you have a small garden you can get a lot of flowers and foliage with vines. They take up a small amount of garden space but can produce hundreds of flowers. You can plant summer flowering vines over large spring blooming shrubs. You can plant them up trees. They can be planted on teepee in your garden bed. Clematis has hundreds of varieties that bloom as early as February and as late as October, so you can have vines blooming for 9 months. These are just a few things that I have done to extend my bloom season from Feb. through frost in my small garden.

I remember trying to do what you have suggested (one bed, in bloom all year round) and found it pretty impossible. I have discovered that it is not necessary to have all the color in one spot. If you a large patch of each plant, your eye will be drawn to that part of the garden when it is in bloom, and ignore the 'sleeping' patches.

I now have something blooming in my garden year round. Whenever I noticed a lull in my garden, I drove around my neighborhood looking to see what was in bloom in other gardens. Then I planted some of that at my house.

You can also search for 'sequence of bloom' guides. Here is a link to several sources: http://www.attra.org/attra-pub/phenology.html#bloom

I suggest you plant lots of evergreen and/or long blooming perennials. Then you can concentrate on some annuals to fill in for the summer.

If you have a favorite flower, you can plant several different types to get a longer bloom season, or keep looking and you may find an evergreen type. Some plants come in both annual and perennial types. Just do lots of research.

Daphne in Tacoma

Here is a link that might be useful: winter evergreen plants

I love this book. It is an English book but works well for our climate.

Here is a link that might be useful: A Garden For All Seasons

This book is written by an East Coast author and not all of the plants are common here but much of her advice is excellent.

Here is a link that might be useful: Year Round Landscaping

I've found Ann Lovejoy's book "Further Along the Garden Path ...a beyond the basics guide to the gardening year" to be very useful and inspirational along these lines....while it is about 50% focused on what to do when it is also full of pictures and information about keeping your garden interesting all year and IT IS FROM THE PACIFIC NORTHWEST (Seattle) so it is pretty accurate for our climate.
It's one of those pretty books that I've actually gotten dirty from use...in the same category as The Well Tended Perennial Garden and Making More Plants!
jwww