As much as I adore daylilies, I could never have a garden of daylilies alone. The most obvious reason is because I live in northern Utah, and we don't get much repeat bloom on our daylilies, with the exception of Stella D' Oro, of course.
But even if you live in a southern daylily paradise, there are reasons to provide companion plants for your daylilies. The most practical reason is because biodiversity is good for the garden. I read an article that quoted a large-scale daylily grower who says that he doesn't expect daylily rust disease to be a serious problem for home gardeners because they grow their daylilies alongside other plants, instead of as a monoculture. Some companion plants also attract beneficial insects, which help to control pests.
Another reason to provide companions for your daylilies is to emphasize the intrinsic beauty of the daylily. One of the basic rules of garden design is that plants with flowers or foliage of different shapes, sizes, textures or colors should be juxtaposed against each other. This makes the garden more interesting. And you know what they say: Variety is the spice of life.
Here are some of my favorite companion plants for daylilies:
Asclepias tuberosa (Butterfly Weed) -- This bright orange wildflower looks right at home with most daylilies.
Campanula carpatica (Carpathian Harebell) -- You can't go wrong with blue-flowered companion plants. This little gem is nice at the front of the border or peeking between the plants.
Campanula rotundifolia (Bluebells of Scotland) -- The masses of lavender-blue bells look fabulous with daylilies of any color.
Coreopsis -- There are annual and perennial varieties to choose from, all of which look great with daylilies. Coreopsis verticillata 'Moonbeam' is one of my favorite companion plants because it brings out the yellow-green color in the throat of most daylilies.
Cosmidium 'Phillipine' -- I can't understand why this wildflower is so rarely grown. It has an exceptionally long bloom season, and the color is very unusual. It looks good next to daylilies in warm colors.
Cosmos 'Sonata White' -- This is the only cosmos that I would plant next to daylilies. Most cosmos are too tall, and they come in bright, purplish-pink shades that clash with daylilies, but these simple, white flowers go with everything.
Daffodil (Narcissus) -- Obviously, daffodils don't bloom at the same time as daylilies. But I've included them because they are famous companion plants for daylilies. You've probably heard of planting daffodils with daylilies so that the dying daffodil foliage is hidden amongst the new leaves of the daylilies. This makes it possible to get two seasons of bloom in the same space. You can do this with Alliums, too. Your friends will wonder about those strange plants that have daylily foliage and allium flowers.
Echinacea (Purple Coneflower) -- Some people think that purple coneflowers clash with warm daylily colors. But I've tried them next to daylilies of all colors and never had a problem. I think the orange-brown cones balance the purple petals. But gardeners who are very sensitive might prefer white echinacea.
Liatris (Blazing Star) -- The fluffy, purple spikes look great with late-blooming daylilies, especially the yellow or gold ones.
Chinese Trumpet Lily -- Tall lilies add height, but they don't crowd the daylilies or become invasive like some other perennials do.
Nicotiana alata (Flowering Tobacco) -- Nicotiana starts blooming in my garden with the late daylilies. The white flowers close up in the heat of the afternoon, but they open again in the evening, perfuming the air with a sweet fragrance. This gives the tired daylily garden new life. (Don't you just hate it when you have a party in the evening, and all the daylilies croak just before the guests arrive?)
Nigella hispanica -- Another blue flower. This self-sowing annual blooms later than its cousin, Nigella damascena. Here's a picture with Zephyr's Song.
Perovskia atriplicifolia (Russian Sage) -- This large, bushy perennial has aromatic, gray-green foliage with soft spikes of lavender-blue flowers from mid summer to fall. It makes a great backdrop for daylilies, as seen in this picture.
Platycodon grandiflorus (Balloon Flower) -- Here's a perennial that won't take over the daylily garden. Balloon flower starts blooming with the midseason daylilies and continues into autumn. It doesn't spread or self sow much, so it never becomes a nuisance.
Ratibida columnaris (Mexican Hat) -- This little wildflower blooms the first year from seed and makes a nice filler for the daylily garden. It's perfect for the prairie look.
Rudbeckia hirta (Black-eyed Susan, Gloriosa Daisy) -- One of the loveliest daylily gardens I ever saw included a large patch of Rudbeckia hirta.
Scabiosa atropurpurea -- This self-sowing annual is usually seen as a mix, but I have a plain white that goes with everything.
Scutellaria resinosa (Prairie Skullcap) -- This rare perennial has a lot going for it. It is compact and drought tolerant, and it blooms in a stunning shade of deep blue that never clashes with other colors.
Sweet Peas (Lathyrus odoratus) -- I used to think that sweet peas could only be grown on a trellis or fence, until I moved to my new house where I didn't have any supports handy. Now I grow them throughout the garden as a filler. I love how they sprawl between the other plants. They are best with tall daylilies that can rise above them, as shown in picture with Sweet Pea 'Matucana'.
Violas (Pansies, Johnny Jump-Ups) -- These form a groundcover in one of my daylily beds, helping to keep the weeds down and adding early spring color at the same time.
