Diablo Ninebark (Physocarpus opulifolius ‘Monlo’ or ‘Diabolo’) is a favored shrub, known for its distinctive dark foliage and adaptability. It provides visual interest throughout the seasons and integrates well into various garden styles.
Characteristics for Landscaping
Diablo Ninebark features deep purple to burgundy foliage, resembling maple leaves. Its color is most intense in full sun, but may green in hot climates or partial shade. In late spring to early summer, small, pinkish-white flowers emerge, contrasting with the dark leaves. These blooms attract pollinators like bees, hummingbirds, and butterflies.
After flowering, the shrub produces small, reddish fruit in the fall, which can attract birds. As the plant matures, its bark exfoliates, peeling in strips to reveal reddish-brown inner bark, providing winter interest. Diablo Ninebark grows with an upright, spreading habit, often forming a fountain shape, reaching 6 to 10 feet in height and spread. It is hardy in USDA zones 2 to 8 and adapts to various soil conditions, preferring well-drained locations.
Designing with Diablo Ninebark
Diablo Ninebark’s dark foliage makes it versatile for landscape designs. It can serve as a specimen plant, drawing attention with its rich color and unique form. Its size and dense branching also make it suitable for informal hedges or privacy screens, providing a lush, dark backdrop.
The deep burgundy leaves create contrast within mixed shrub borders or perennial beds. Planting it behind lighter-colored foliage plants, such as those with lime green, gold, silver, or variegated leaves, highlights its dark tones. Companion plants like ‘Goldmound’ spirea, ‘Limelight’ Hydrangea, or yellow-eyed grass complement its appearance. Diablo Ninebark can also be integrated with brightly colored flowering perennials, such as pink coneflower or tall verbena, where its dark leaves provide a visual anchor.
Beyond its color, the shrub’s arching branches and exfoliating bark contribute texture and interest throughout the year. This allows it to define spaces or guide the eye along pathways. Used as a foundation plant or in mass plantings, Diablo Ninebark adds depth and structure to garden compositions.
Planting and Care
An appropriate planting location is important for Diablo Ninebark to thrive. It performs best in full sun, receiving at least six hours of direct sunlight daily, which encourages the deepest foliage color. While it tolerates partial shade, purple leaves may green up in such conditions. Good air circulation around the plant promotes overall health.
Diablo Ninebark adapts to various soil types, including clay and rocky soils, but prefers well-drained, moderately moist, slightly acidic soil. Avoid overly wet or soggy conditions, as the plant does not tolerate standing water. When planting, dig a hole twice as wide as the root ball and of similar depth, ensuring the top is level with the surrounding soil. Space plants 6 to 8 feet apart for ample room and air circulation.
Consistent watering is needed during the first growing season to establish the root system, once or twice a week during dry periods; once established, Diablo Ninebark becomes drought-tolerant, requiring water primarily during extended dry spells or extreme heat. Pruning is best performed immediately after flowering in late spring or early summer to maintain shape or rejuvenate the shrub. Older, heavier stems can be cut back by up to one-third or to the ground every few years to encourage new growth and vigor. The plant is resistant to most pests and diseases, though it can experience powdery mildew and aphids. Good air circulation and proper watering can help mitigate these issues.