African feather grass (Pennisetum macrourum)

Overview

African feather grass, scientifically known as Pennisetum macrourum, provides substantial linear texture to the landscape with its upright, arching, narrow green leaves. This rapid-growing, clump-forming ornamental grass is valued for its stature, often reaching 3 to 6 feet high, capped by distinctive cylindrical flower panicles rising above the foliage. While highly ornamental, gardeners must appreciate its vigorous nature, as Pennisetum macrourum spreads readily by self-seeding and rhizomes.

Native to southern Africa, this grass thrives as a tender perennial in warm climates, demonstrating adaptability across various soil types, including heavier clay soils. Its relatively low maintenance requirements make it an attractive choice for gardeners seeking substantial visual impact without intensive routine care once established.

Despite its beauty, the aggressive spreading habit of African feather grass leads to its inclusion on several noxious and regulated weed lists across the United States. Prudent placement is key to utilizing the architectural strength of Pennisetum macrourum successfully in any design.

Fast Facts

• Plant Family: Poaceae
• Plant Type: Ornamental grass
• Native Range: Southern and eastern Africa
• Hardiness Zones: USDA Zones 8-10
• Size at Maturity:
  • Height: 3-6 ft
  • Spread: 2-3 ft
• Bloom Time: June to August
• Bloom Description: Green to yellow-green sometimes tinged with purple, yellow or brown
• Sun Exposure: Full sun to part shade
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

Planting Pennisetum macrourum is best done when conditions are warm, allowing this warm-season grass to establish firmly before winter dormancy, especially in cooler portions of its hardiness range (Zones 8-10). Ensure the chosen location provides full sun for the best flower production, although it tolerates light shade. The species is adaptable, performing well in fertile, medium soils that drain adequately, but it notably tolerates clay soils better than many alternatives.

Water needs are medium. While established clumps exhibit good drought tolerance, consistent moisture will promote the vigorous growth characteristic of African feather grass. Fertilizing is generally unnecessary, aligning with its low maintenance profile, though very lean soils might benefit from minimal compost application at planting.

Because this grass spreads via underground rhizomes and prolific self-seeding, aggressive management may be required to keep Pennisetum macrourum confined to its intended area. Pruning typically involves cutting back the dead foliage close to the ground in late winter or early spring before new growth begins, rejuvenating the clump for the season ahead.

Landscape Uses

The primary recommended use for African feather grass is naturalizing landscapes where its spreading tendency is desired or manageable, creating large, textural colonies. It excels in settings where a bold, architectural presence is needed, such as screening or mass plantings along property lines or large open areas.

For gardeners in containers, Pennisetum macrourum serves as an excellent specimen plant, offering vertical accent. If grown this way, the pots must be moved to a protected, unheated location or indoors for winter in zones colder than Zone 8 to ensure the plant survives until spring planting.

When spacing is critically managed, these grasses can provide soft, feathery texture borders without overwhelming surrounding perennials. However, always pair this vigorous grass with robust companions that can compete effectively against its rhizomatous spread.

Flower Qualities

• Showy

Noteworthy Characteristics

Pennisetum macrourum, commonly called African feather grass, is a tender perennial grass that is native to southern Africa, tropical Africa and the Arabian Peninsula (Yemen), and it has since been introduced to various other parts of the world. Notwithstanding its ornamental beauty, it is notorious for spreading invasively by rhizomes and self-seeding in regions like the southern U.S. and Australia, leading to its listing on the U.S. Noxious Weed List. This rapid-growing, clump-forming grass produces upright, arching, narrow, linear green leaves topped by cylindrical flower panicles rising to 5-6’ tall, with spikelets surrounded by finely-barbed feathery bristles.

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Tolerances

• Clay Soil

Potential Problems

The primary concern when growing Pennisetum macrourum is its vigorous spreading nature; it can quickly naturalize aggressively via rhizomes and abundant self-seeding, potentially choking out neighboring desirable plants. Because this characteristic is inherent, gardeners must plan for containment from the outset, or avoid planting it where spread is undesirable.

Fortunately, African feather grass generally experiences no serious insect or disease issues. Management of its spread is predominantly cultural; for perennial survival outside Zone 8, container culture is recommended, or diligent removal of seedlings where necessary in warmer zones to prevent overpopulation.

Frequently Asked Questions

What hardiness zones is African feather grass suitable for?

Pennisetum macrourum is winter hardy in USDA Zones 8 through 10.

How large does Pennisetum macrourum grow?

This ornamental grass typically achieves mature heights between 3 and 6 feet tall, spreading to a width of 2 to 3 feet wide.

What sun exposure does African feather grass need?

For optimal performance, plant Pennisetum macrourum in full sun, though it will tolerate partial shade.

When does African feather grass bloom?

The plant produces flowers from June to August, with blooms described as light green to yellow-green, sometimes showing hints of purple, yellow, or brown.

Conclusion

African feather grass provides exceptional texture and height with minimal required maintenance, making Pennisetum macrourum a powerful specimen in large-scale plantings or as a robust container plant. Remember that this beauty comes with an invasive tendency, so careful site selection is crucial for gardeners considering this species. Check your local regulatory lists before planting African feather grass and plan for spatial control accordingly.

Companion Planting Strategies

When integrating Pennisetum macrourum into a full-sun border, choose companions that are equally tough or thrive on similar medium water needs. Coneflowers (Echinacea) or Black-Eyed Susans (Rudbeckia) offer contrasting flower shapes and thrive in the same sunlight intensity. For a drier, textural pairing after the bloom period, consider Blue Fescue (Festuca glauca), though ensure the African feather grass rhizomes do not encroach upon the fescue’s preferred space.

Design Ideas Using Architectural Grasses

Utilize the strong vertical lines of Pennisetum macrourum to provide year-round structure when paired with broadleaf evergreen shrubs. Planting the grass in drifts against a dark backdrop, like a hedge of ‘Green Velvet’ Boxwood, will dramatically highlight the movement and color variations in the flower plumes during summer. In modern or minimalist designs, a single, large mass of African feather grass can function as a living sculpture, drawing the eye upward.