Pennisetum Setaceum: An Invasive Ornamental Grass
Introduction
Pennisetum setaceum, also known as fountain grass or purple fountain grass, is a popular ornamental grass that is prized for its attractive foliage and graceful appearance. Native to Africa and the Middle East, this plant has been widely cultivated for its ornamental value in gardens and landscapes around the world. However, despite its beauty, Pennisetum setaceum is considered an invasive species in many regions, where it can outcompete native plants and disrupt ecosystems.
Description
Pennisetum setaceum is a perennial grass that typically grows to a height of 2-4 feet, with a spread of 1-2 feet. It has narrow, arching leaves that are a deep green color, with a purplish tint at the base. The plant produces feathery, pinkish-red flower spikes that rise above the foliage in late summer and fall, adding a dramatic and colorful accent to the landscape.
Propagation
Pennisetum setaceum is easy to propagate from seed or division. The seeds can be sown directly in the garden in spring, or started indoors and transplanted once the danger of frost has passed. Division is also a simple method of propagation, as the plant forms dense clumps that can be divided in early spring or fall.
Care and Maintenance
Pennisetum setaceum is a relatively low-maintenance plant that thrives in full sun and well-drained soil. It is drought-tolerant once established, making it a good choice for dry gardens or xeriscaping. The plant should be watered regularly during the first growing season to help establish a strong root system, but after that, it can survive on natural rainfall.
Invasive Potential

Despite its popularity as an ornamental plant, Pennisetum setaceum is considered invasive in many regions, including parts of the United States, Australia, and the Mediterranean. The plant has a high reproductive rate and can spread quickly, displacing native vegetation and altering ecosystems. In some areas, it is prohibited or restricted due to its invasive potential.
Control Measures
Controlling Pennisetum setaceum can be challenging, as the plant spreads by both seed and rhizomes. Regularly removing flower spikes before they set seed can help prevent further spread, as can digging up and disposing of any new shoots that appear. In some cases, herbicides may be necessary to control larger infestations, but care should be taken to avoid harming non-target plants.
Alternative Plants
For gardeners looking for a similar ornamental grass that is not invasive, there are several alternatives to Pennisetum setaceum. Some options include Miscanthus sinensis, Panicum virgatum, and Schizachyrium scoparium, all of which offer similar texture and color without the invasive tendencies of fountain grass.
Conclusion
Pennisetum setaceum is a beautiful and popular ornamental grass that can add texture and color to gardens and landscapes. However, its invasive potential makes it a risky choice for many regions, where it can disrupt native ecosystems and cause significant harm. Gardeners should be aware of the risks associated with this plant and consider alternative options that offer similar beauty without the threat of invasiveness. By making informed choices in plant selection, we can help protect our natural environments and preserve biodiversity for future generations.
