Blue Lyme Grass
Leymus arenarius (formerly Elymus arenarius) · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Triticeae
Grass Category
Ornamental Grass / Erosion Control / Coastal Sand Stabilizer
Variety / Cultivar
Likely 'Findhorn' or 'Blue Dune' based on vibrant steel-blue foliage height and intensity
Hardiness Zones
USDA Hardiness Zones 4-9; excellent cold tolerance; goes dormant in winter, turning a tan/straw color.
About This Grass
A striking ornamental grass known for its stiff, upright, steel-blue foliage and architectural form. Reaches about 2-3 feet in foliage height, with straw-colored flower spikes (resembling wheat) rising above the leaves in mid-summer. Texture is coarse and the plant maintains a rugged, upright appearance.
Blade Characteristics
Coarse width (5-15mm), flat or slightly inward-rolling (involute), sharply pointed tips. Distinctive glaucous blue-gray or steel-blue color due to a waxy coating. Blades are stiff and leathery with prominent parallel veining. Ligule is short and membranous; auricles are usually present and clasping.
Root System
Deep, extensive rhizomatous root system. High thatch-forming tendency and extremely fast establishment speed. Ideal for stabilizing loose soils but can be invasive in residential garden beds.
Growing Information
Origin Region
Northern and Western Europe; adapted to temperate coastal regions and sandy soil conditions
Growth Habit
Rhizomatous (vigorously spreading underground); forms dense, aggressive colonies over time
Sunlight & Water Needs
Full Sun (requires at least 6-8 hours for best color); low-to-moderate water needs; high drought tolerance once established. Prefers well-drained sandy or loamy soils and tolerates a wide pH range.
Mowing & Maintenance
Not typically mowed as turf. Maintenance involves cutting back to the ground in late winter or early spring before new growth begins. Fertilization is rarely needed (Low maintenance level).
Special Characteristics
High salt tolerance (ideal for seaside planting), excellent erosion control for slopes and dunes, high wind resistance. Highly aggressive spreader that can crowd out other plants if not contained by root barriers.
Ecological Information
Introduced/Naturalized in North America; provides excellent soil stabilization in coastal ecosystems. Offers cover for small wildlife and birds. Can be considered invasive in specific sensitive sandy habitats outside its native range.