Purple Fountain Grass (\(Pennisetum\) \(setaceum\) ‘Rubrum’) is an ornamental grass known for its deep burgundy foliage and gracefully arching, plume-like seed heads. It provides color and texture, serving as a unique focal point in garden beds and containers. Successful companion planting requires selecting partners that share similar growing needs and enhance the grass’s visual appeal. Understanding its specific environmental requirements and applying thoughtful design principles ensures a cohesive garden composition.
Environmental Needs of Purple Fountain Grass
Any companion plant must tolerate the conditions Purple Fountain Grass prefers. The grass thrives in full sun, requiring at least six to eight hours of direct sunlight daily to maintain its rich, dark color and upright habit. Insufficient light causes the foliage color to fade and results in a weaker structure.
The soil must be well-draining, though the grass needs consistent moisture during establishment. Once mature, \(Pennisetum\) \(setaceum\) ‘Rubrum’ shows moderate drought tolerance, making it a robust choice for sunny, hot areas. It grows in a mounding, clumping habit, typically reaching three to four feet in height and width in a single season. Because it is a tender perennial, it is usually grown as an annual in climates colder than USDA Hardiness Zone 9.
Selecting Plants for Color and Texture Contrast
Successful companion planting requires contrast. The fine, wispy texture of the grass blades and its soft, fuzzy plumes need a visual counterpoint. Partnering the grass with plants that have coarse, broad, or succulent leaves provides the textural difference to make both plants prominent.
Color selection is important, as the deep purple and reddish tones of ‘Rubrum’ are highlighted by complementary hues. Colors opposite purple on the color wheel, such as bright yellow, lime green, and silver, will make the foliage appear richer and more intense. For a cooler look, deep indigo or true blue flowers create a harmonious blend instead of a stark contrast.
The mounding nature of Purple Fountain Grass, which reaches three to four feet, dictates companion placement. Low-growing plants should be used at the base or front as a groundcover layer. Mid-height plants, growing to a similar height, can be interplanted to create a flowing tapestry effect. This layering strategy ensures all plants receive adequate light and contributes to a balanced display.
Specific Companion Plant Recommendations
Annual Options
Annuals are an excellent choice for pairing, as they provide season-long color that matches the vigorous growth habit of the grass. The trailing Sweet Potato Vine (\(Ipomoea\) \(batatas\)) is a perfect textural match, especially chartreuse or lime-green varieties like ‘Margarita’ or ‘Sweet Caroline Green’. This color contrast powerfully offsets the burgundy of the grass.
Sun-loving Petunias are a classic companion, offering a vibrant burst of color and a lower profile. Bright pink, white, or deep magenta petunias create a complementary color scheme and thrive in full sun. Dusty Miller (\(Jacobaea\) \(maritima\)) is another strong annual selection, providing silvery-gray, felted foliage that contrasts both the texture and color of the dark grass.
Perennial and Structural Options
For permanent garden beds, perennials must match the grass’s preference for full sun and well-drained soil. Coneflowers (\(Echinacea\)) are a reliable choice; their stiff, upright stems and daisy-like blooms provide a strong textural contrast to the grass’s softness. Bright yellows and oranges of certain cultivars create a striking visual impact next to the purple foliage.
Russian Sage (\(Perovskia\) \(atriplicifolia\)) offers contrasting color and texture with its silvery foliage and vertical spikes of lavender-blue flowers. Its woody structure and airy presentation pair well with the movement of the fountain grass. Fall-blooming Sedum varieties, such as ‘Autumn Joy’, also work well, featuring thick, succulent leaves and dense flower heads that create a coarse texture against the fine grass blades.
Low-Water Options
Low-water perennials that tolerate sun are suitable for planting around the base of the grass where the soil dries quickly. Low-growing, creeping Sedums, such as ‘Lemon Coral’, offer lime-green foliage that spills over the edge of the planting area. These succulents require little moisture once established and provide an intense color highlight against the dark grass.
Hens and Chicks (\(Sempervivum\) species) also offer a dense, rosette-forming structure that contrasts sharply with the linear form of the grass, enhancing the visual diversity of the garden composition.