Companion planting pairs up plants, flowers and grasses with others that share certain characteristics or design features. The hardy hibiscus, with its showy, often two-toned flowers, attracts companion plants from across the spectrum. Nearly always, the towering hibiscus will act as the backdrop to other plants, or as the central feature in a perennial border or sunny flowerbed. It's late-flowering, so its foliage also provides a green background for many smaller, colorful, early-blooming annuals.
Plant a host of spring bulbs in the hibiscus bed. You'll be taking advantage of the hardy hibiscus' tendencies toward late blooming. Start with early-blooming crocuses and daffodils, that will bloom and fade before the hibiscus even begins greening.
Plant mid-spring bloomer bulbs, such as tulips and Siberian iris, to accompany the first greening shoots of your hardy hibiscus. Layer the bulbs in a zigzag border about 8 inches in front of the hibiscus roots for maximum visual effect.
Interplant your hardy hibiscus with giant feather grass (Stipa gigantea), a hardy perennial that reaches 6 feet tall with purple, green and golden flower heads. Add a shorter grassy companion, silver spike grass (Spodiopogon sibericus) for 4-foot green and silver foliage topped with rose-like flowers.
Display an exotic visual, showcasing the tall, showy hibiscus by planting calla lilies (Araceae) in a front border. They'll grow to 3 feet high, with 6-inch trumpet-like flower heads in tropical colors, such as peach, mango, yellow, pink and rose.
Keep your hibiscus' feet cool and weed-free by choosing low-growing annuals to mound and spread just a few inches off the ground. In late June, before the hibiscus blooms, plant carpets of impatiens (Balsaminaceae) in colors to complement or contrast with the hibiscus. They'll all bloom together into early fall.
Attract hummingbirds to your hardy hibiscus garden by companion planting with the gently nodding columbines, (Ranunculaceae). These will grow to be a foot tall or more, and begin blooming in late spring. Their flowers will fade away just as your hibiscus are coming to full bloom.