Controlling Invasive Blue Dune Grass (Leymus arenarius)

A gardener planted blue dune grass (Leymus arenarius) 2 years ago, now spreading under weed fabric into reed grass and lawn. Rhizomatous spread.

Why It's Winning

• Rhizomes run deep and far, popping up everywhere.
• Weed fabric only slows—rhizomes go under/through.
• Outcompetes weaker neighbors.

Control Strategies (Ranked)

1. Physical removal (best): Dig out every rhizome fragment. Sift soil. Repeat monthly. Exhaust reserves.
2. Rhizome barrier: 24" deep HDPE barrier around kept clump. Cut rhizomes at barrier line annually.
3. Herbicide (targeted): Glyphosate (Roundup) painted/wiped on leaves of unwanted shoots. Do not spray—kills neighbors. Cut rhizome, dip cut end in concentrate, bury near mother plant (translocates).
4. Smothering: Heavy cardboard + 12" mulch for 2 years. Only for areas you can sacrifice.
5. Replace: Remove entirely. Plant clump-forming grasses: Calamagrostis 'Karl Foerster', Panicum 'Shenandoah', Schizachyrium 'The Blues'.

Lawn Invasion

In lawn: mow low, then paint glyphosate on regrowth. Or dig plugs. Reseed bare spots.

Reed Grass Rescue

Dig reed grass, wash roots, remove all blue dune rhizomes, replant in clean soil.

Blue dune grass is a thug. Containment or removal are the only real solutions.