Cannas bring a dramatic, tropical flair to any garden space. They are grown for their bold, often colorful foliage and vibrant, hot-toned flowers, creating an immediate focal point. Strategic companion planting maximizes their aesthetic impact by selecting partners that enhance their appeal rather than competing with it. The goal is to create a cohesive, layered display using contrasting textures and complementary colors.
Understanding Canna Needs
Successful companion planting requires respecting the canna’s specific cultural needs, which narrows the field of suitable partners. Cannas are tropical plants that perform optimally with ample sunlight, requiring a minimum of six to eight hours of direct sun daily for the best flowering and foliage color. In extremely hot climates, afternoon shade can prevent the large leaves from scorching.
Cannas are heavy drinkers, thriving in consistently moist soil. The soil should be rich in organic matter to hold moisture, yet still well-draining. Some varieties can even grow in shallow water. Any companion chosen must tolerate or prefer this high-moisture environment, as the canna’s water demand dictates the watering schedule for the entire grouping.
Companions for Contrasting Foliage
The massive, paddle-shaped leaves of the canna (green, bronze, or variegated) provide a strong, coarse texture that requires balancing elements. Introducing plants with fine or lacy foliage creates a dynamic textural contrast, making the canna’s bold structure stand out. Ornamental grasses, such as Japanese forest grass or fountain grass, offer delicate, arching blades that soften the rigid, upright lines of the canna stems.
For contrast in color and form, bright chartreuse or dark purple cultivars of sweet potato vine (Ipomoea batatas) are effective as ground cover or container “spillers.” This plant offers a different leaf shape and a dense, trailing habit for a lush foreground. Plants with silvery-gray leaves, like Dusty Miller (Senecio cineraria), provide a cooling color contrast to the warm tones of the canna’s foliage and blooms. Similarly, the huge, contrasting leaves of elephant ears (Colocasia) amplify the tropical theme while sharing the canna’s preference for abundant water.
Pairing Plants for Complementary Blooms
Selecting flowering companions involves complementing the canna’s usual bloom colors—yellow, orange, red, and pink—while paying close attention to plant height for a layered effect. Lower-growing plants are practical, as they effectively mask the canna’s sometimes bare lower stems, creating a visually dense display. Annuals like zinnias are excellent partners, offering vibrant, daisy-like flowers in similar hot colors that extend the canna’s high-energy palette.
For a cool-color contrast, spiky-flowered plants such as Salvia, particularly in deep blue or violet hues, work well against the round, warm-toned canna flowers. The verticality of salvia’s blooms provides a distinct shape that prevents the grouping from looking too uniform. Dahlias share the canna’s need for consistent moisture and rich soil, making them a great fit for adding mid-level height and intricate bloom shapes. Lantana and Marigolds thrive in the same sunny, warm conditions and introduce a smaller, vibrant bloom size that fills the spaces beneath the canna canopy.
Placement and Maintenance Considerations
Effective placement ensures that each plant has the necessary space to flourish without overcrowding the canna. When planting, consider the mature spread of canna varieties; taller types need up to three feet of space between rhizomes to prevent competition for light and nutrients. In garden beds, position cannas toward the back or center to serve as the “thriller” element, allowing shorter companions to form the middle and front layers.
Container plantings require a similar approach, where the canna acts as the tall, central element, surrounded by “filler” plants like coleus and “spiller” plants like sweet potato vine trailing over the edge. Maintenance focuses on meeting the high-water needs of the cannas, necessitating deeply watering the entire grouping at least once a week, or more frequently during dry spells. Mulching the area helps retain soil moisture, benefiting all moisture-loving companions planted alongside them.