Roses are some of the most beautiful and popular flowers in the world, according to information published by the University of Illinois. Fragrant and colorful, they vary from compact bushes, large hedges, or climbing varieties. Flowers planted near roses should not compete with their extensive root systems or suffer from diseases that can affect roses. Companion plants for roses should also visually complement the flowers and benefit the roses.
Rosemary (Rosmarinus officinalis)
While the flowers on this herb are rather insignificant, these and other herbs are excellent for planting near roses because they have the same care requirements (lots of sun and well-draining soil) and because they rarely suffer from broad-leaf diseases that can spread to roses, such as leaf spot. The silvery-green, spiky leaves of rosemary complement the more rounded shape of the roses, and the shrub is very hardy--rosemary can even survive periods of drought--letting you concentrate on maintaining the health of the roses. Rosemary grows best in United States Department of Agriculture (USDA) hardiness zones 8 through 10.
Clematis (Clematis sp.)
Clematis is often planted behind rosebushes, especially short varieties. This climbing vine looks stunning when framing roses, and the rose bushes shade the roots of this plant, which require cool soil. Clematis needs sun and slightly moist soil just as roses do, and although it can suffer from the same fungal diseases as roses, these disease are easily preventable with an application of fungicide in the spring. Although there are many varieties of clematis, they are all quite hardy. In general, clematis plants can be grown in USDA hardiness zones 4 through 11, with some cultivars able to stand the cold in zone 3. With over 250 species of this colorful vine, according to Jane C. Martin, a horticulturist with Ohio State University, you are sure to find one that will complement your roses nicely.
Blue Asperula (Asperula orientalis)
Blue asperula is an easy-to-grow, hardy plant. The 12-inch tall, thin tubular flowers of the plant are just the right height to fit under and around most rosebushes, and the blue color is a striking contrast to the reds, pinks, creams and yellows of most roses. The plant also attracts hummingbirds, which eat the aphids that so often plague roses. The light, pleasing fragrance of blue asperula (also sometimes called blue woodruff) does not overwhelm that of fragrant roses. Blue asperula grows well in fertile, well-drained soil and thrives in the shade cast by roses. This plant, which blooms profusely through the summer and into early fall, self-seeds and spreads rapidly. Plant Asperula orientalis in USDA hardiness zones 4 though 9 for best results.