Blue Dune Grass (Leymus arenarius): Invasive Risk and Management in a Manicured Pool Area

Blue dune grass (also called blue lyme grass) is a stunning but aggressively spreading rhizomatous grass. In a meticulously maintained stone pool surround, it will eventually escape control.

Can You Contain It?

• Short term: Vigilant plucking of runners may work for 1–2 years.
• Long term: Rhizomes travel under fabric, stone, and edging. They will appear in lawn and neighboring beds.

Better Alternatives for Blue Foliage

• Blue fescue (Festuca glauca) – clumping, 10–12 inches, non-invasive.
• Blue oat grass (Helictotrichon sempervirens) – clumping, 2–3 feet, striking.
• 'Elijah Blue' fescue – intense blue, tidy mound.

If You Keep It

Install a deep (18–24 inch) root barrier (HDPE plastic) around the planting pocket. Monitor monthly. Be prepared to remove it entirely if it breaches.

Gracillimus maiden grass (Miscanthus sinensis 'Gracillimus') will bulk up by mid-summer with warm weather, water, and nitrogen fertilizer.