Ornamental grasses add texture, height, and color to your landscape, enhancing its visual appeal. While they are a key element in many garden design layouts, it’s important to choose your desired variety wisely. Certain ornamental grasses self-seed prolifically and have vigorous underground rhizomes that make them extremely difficult to remove once established. The next time you’re perusing your local garden center for ornamental grasses, our experts warn against adding these cultivars to your cart.
Maiden Grass
Miscanthus sinensis ornamental grass.
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Maiden grass (Miscanthus sinensis) is a warm-season perennial grown for its lush green foliage and feathery plumes. Despite its appeal, it’s best to keep this plant out of the landscape. “It displaces native plants, forming dense monocultures in fields, roadsides, and open woodlands, which severely reduces biodiversity,” says Mary Phillips, head of native plant habitat strategy and certifications at the National Wildlife Federation.
Maiden grass spreads prolifically through wind-dispersed seeds and vigorous underground rhizomes, making it hard to remove once established. Instead, Phillips recommends growing Indiangrass, a tall, warm-season perennial grass with blue-green summer foliage that transitions to golden-yellow in fall.
Fountain Grass
Purple fountain grass is treated as an annual in cold climates.
Credit: David Beaulieu
Fountain grass (Pennisetum setaceum) produces fine-textured foliage that is topped by dense seed heads resembling bottle brushes. Despite its uniqueness, Phillips recommends avoiding planting fountain grass. “It spreads aggressively via wind-blown seeds, which can remain viable for years, allowing it to quickly take over and smother native plants,” she says.
Additionally, in hot, dry areas, the dried foliage can be highly flammable, increasing the risk of wildfires. “Even varieties labeled hybrid or sterile can carry risk, as they may still produce some viable seeds that contribute to the spread of the invasive population,” she notes.
Pampas Grass
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Pampas grass (Cortaderia selloana) is perfect for adding texture to flower arrangements, but keep it out of your garden. “It produces millions of wind-dispersed seeds, allowing it to rapidly colonize and form dense, massive clumps that smother native habitats,” says Phillips.
Like fountain grass, pampas grass poses a wildfire risk due to its huge volume of dry, dead material. As an alternative, Phillips recommends growing switchgrass—a versatile, warm-season perennial grass known for its fluffy seedheads and colorful foliage.
Chinese Silver Grass
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Chinese silver grass (Miscanthus sinensis) produces beautiful flower heads that add interest to the landscape. It is a large ornamental grass that is often grown as a hedge or barrier. However, certain varieties readily self-seed.
“The rhizomatous habit (growing from underground growth structures) makes removal difficult,” says Damon Abdi, assistant professor of landscape horticulture at Louisiana State University AgCenter. “Consider a sterile or low-seeding variety of Miscanthus in order to capture the features you want without inviting more maintenance than would be desirable.”
Bamboo
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Bamboo (Bambusa) is a fast grower that creates a dense screen, making it a popular choice among some gardeners who want to add privacy around their home. But Abdi recommends being cautious about species selection.
“Some bamboo varieties have a clumping form where spreading is not a major concern, whereas other varieties have a more spreading habit via fast-growing underground rhizomes, which can cause problems if left unchecked,” he says. “Selecting clumping form bamboo would be preferable, as the running types of bamboo can quickly get out of hand.”
Mexican Feather Grass
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Mexican feather grass (Nassella tenuissima) features fine-textured foliage and flowers that Abdi says add interest to the landscape. “However, outside of its native range (Texas, New Mexico, parts of South America), this plant can spread undesirably, particularly with its prolific seed production,” says Abdi. Only grow it in its native habitat to keep it in check.
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