Certain color families seem to work best together. The first major break is between warm colors and cool colors. They can be used together or separately. When used together, one might select cool colors as the background and then make accents of warm colors, or we can make the background warm and then add cool accents. In my personal experience, the most relaxing gardens have cool colors as the background with warm tones as accents. However, if you are energized by warm colors and enjoy their bright sunny glow, you might want to consider using warm tones in the background.
Daylilies come in a wide array of colors. Ranging from near-white to near-black, most tones are found in daylily flowers, and many flowers have interesting combinations of one or more colors. The most common colors are yellows and golds, with orange also being common in many species and hybrids alike. In addition to the species-colors, there are near-white, lavender, pink, red, maroon, and purple daylilies, all the way to heavily pigmented red/maroon/purple flowers that have a near-black appearance, as well as a whole range of pale flesh to peach to melon to dark melon-orange that seem to be based on a 'melon' mutation.
With so many different colors, one might choose to collect them all and have a wide range of variety. That is a perfectly legitimate thing to do. Collector's gardens are often amazing displays of variety and novelty, and are the most wonderful places to learn about the range of daylilies. Most hybridizer's will have a lot of different colors and form, even if they aren't breeding from them all.
However, for the average gardener or homeowner who likes daylilies and wishes to grow some, or for the avid gardener who does not want to specialize in daylilies, there are other, more designed possibilities that can give you great satisfaction with daylilies. Even for those specializing in daylilies there may come a time when a more arranged and designed garden is desired and I hope some of these hints may also help you in making choices in your garden design.
In choosing a garden layout, background color is very important to consider and large plantings of similar colors (or even the same cultivar en masse) can tie the garden together and allow the specimen plantings and other accents to stand out more strongly. Daylilies can make a beautiful garden in and of themselves, but in home gardens and mixed gardens, they can be mixed into the garden in numbers large or small, as desired. When daylilies are used to form the background, either for a mixed garden or of a predominantly daylily garden, it is wise to pick a complementary color to your accent plantings.
So if you have a particular love of purple as the main accent specimens, you might want to choose yellows in shades from palest yellow through canary yellow to create the background to make the purple accents more prominent. If you want dark flowers as your accents, a background of light colors will allow the dark flowers to show up in stark contrast. It is my experience that the best range of tones for a cool background is the near-white through pale flesh melon and pale yellow tones. These allow other colors to stand out, and these tones will complement most other colors. I find these light tones are calming in the garden in mid to late summer when the weather is so hot and they also will often show good sun tolerance, allowing the background to look fresh late into the evening.
For a warm background, bright yellows, oranges, golds, and red tones can be used. These colors and combinations of these colors can be found in many forms of daylilies. The warm tones can be used as a background as a single color (or even a single superior cultivar) or these tones can be mingled for a very fiery effect. I prefer this effect in late spring/early summer - the early daylily season into the early-mid season - when the weather is not so warm as it will be in high summer, and when the bright, cheery colors are very welcome in the landscape. Bright yellows as a backdrop to red specimen plantings can make a lovely, bright effect. I also like large mass plantings of orange, which can have the effect of the ditch lily without the rampant growth and incorporate traits seen in the hybrid daylilies.
The more complex patterns and forms in daylilies are often overwhelming, especially to newcomers. They are extraordinary. While many of us who collect or breed daylilies may have these all over the place, in no particular order or arrangement, gardeners who haven't fallen deep into the addiction may want to focus on these types as accent plants. Now with that said, any daylily can make an interesting accent, if placed well with other colors and textures that make that plant stand out, but the interesting forms and color combinations of the advanced patterns can make an especially eye-catching accent planting.
Using a hot color as an accent point against a cool background can be very attractive, as can a cool color against a hot background planting. Using daylilies with eyes, eyes and edges, patterned eyes, double or triple edges and patterned eyes, or any of the other advanced combination can be especially attractive when the color of the eye and edge or the background color of the flower matches or compliments the colors planted in the background. For instance, a near white flower with burgundy eye and edge can be very attractive against a near white mass background planting, whether of daylilies or other flowering plants. Conversely, the same near white flower with burgundy eye and edge could be very attractive with a background planting of burgundy foliage, plants with burgundy flowers or burgundy self-colored daylilies.
There are many interesting flower forms that can also make for very eye-catching accent plantings. I find that yellow spiders such as Kindly Light can be very attractive in front of a backdrop of hardy banana trees such as Musa basjoo. The large, round-petalled daylily flowers look especially attractive with dinner plate Dahlias and large double-flowered roses. Tall daylilies can make a nice backdrop for most anything, even in wildflower gardens, but I like them very much mixed with tall lilium.
Any especially attention-grabbing daylily can be attractive with a backdrop of simpler daylilies of a matching or complementary color, or with a backdrop of other plant species. In the gardens here, we often use coneflowers and painted daisies as backdrops for mass plantings of daylilies, with the fronts of the borders a mixture of short annuals, perennials and short-scaped daylilies. Try mixing daylilies with other plants, being aware of the combinations of warm and cool tones, complementary or contrasting colors and heights. Or, if you want to focus on a daylily garden, apply the same principles when selecting the cultivars you want to combine to make an attractive planting. Daylilies have a place in every garden, provided that they are well chosen for the environment in which you garden, the particular niche you need them to fill and that you select a cultivar or cultivars that are hardy, durable and will flourish under the effort you wish to put into them.