Daylilies are so colorful and hardy that you could devote an entire garden to them, but why miss out on the variety and texture that companion plants can offer? Whether you have daylilies already in the ground or you're starting a new venture and want to include them, take time to explore possibilities. Work with bloom times, color and overall effect; for good measure, throw in an ever-blooming variety of daylily to tie your plan together.
Late Spring Through Early Summer
Companion plants such as ornamental catmint (Nepeta), the salvias "May Night" and "Blue Hills," and false indigo (Baptisia) are hardy, long-blooming choices in purples and blues to complement the yellow palette of the early daylilies. Besides their color, the low-growing dianthus "Bath's Pink" and the magenta "Firewitch" give a mounding effect in front. The bluish foliage adds extra contrast. Plant annuals such as petunias to weave color in between.
Mid-July through mid-August is prime daylily season, according to Olallie Daylily Gardens in Vermont. Color is more diverse; and flowers are larger and have thicker substance, some having ruffled edges and double forms. Intersperse a few varieties along with an ever-blooming one such as the lemon-yellow "Happy Returns" between purple coneflowers (Echinacea), Russian sage (Perovskia) with its electric blue spikes and silver foliage, and "Becky" Shasta daisies (Leucanthemum "Becky"). Try feather reed grass (Calamagrostis "Karl Foerster") in the back.
Late Summer Into Fall
The late August garden doesn't have to be tired. Sedums are coming into color, perennial sunflowers (Helianthus) and fountain grasses (Pennisetum) are in their glory, and the Russian sage still has its flowers and foliage. Removing spent flowers, also called deadheading, from coneflowers and "Becky" Shasta daisies can prolong bloom. Plant Blue Mist Shrub (Caryopteris) because there's no other blue like it in the late-summer garden. (Check your local USDA hardiness, as it grows in Zone 6-9). And yes, there are late daylilies. Bloomingfields Farm in Connecticut lists several in the Extra-Late category, which in USDA Hardiness Zone 5 goes to the end of September.
Don't Overlook Foliage
You don't always need flowers to complement your daylilies; foliage can be effective as well. Viette Nurseries in Virginia recommends using foliage plants such as Artemisia "Silver Mound" and Heuchera "Caramel" with its warm orange-colored leaves to advantage alongside daylilies and other companion plants.