Blue Dune Lyme Grass

Blue Dune lyme grass (Elymus arenarius 'Blue Dune') is a densely tufted ornamental grass with arching, steel-blue leaves and upright summer seed spikes. Long rhizomes make it a vigorous, spreading plant, so its mature footprint can extend far beyond the initial clump. [RHS](https://www.rhs.org.uk/plants/360512/leymus-arenarius-blue-dune/details) · [Kansas State University](https://www.k-state.edu/turf/resources/ornamental-grasses/grasses/leymus-arenarius.html) ## Form and siting Plant it in full sun and well-drained soil. The RHS lists chalk, loam, and sand, with a mature height of 1–1.5 metres and spread wider than 8 metres. Kansas State observed 36–48 inches of height and 24–32 inches of width in the first two years. The blue foliage suits open coastal or prairie-style plantings, and the rhizomes can help stabilize loose sand, but this grass is difficult to contain in a small garden. [RHS](https://www.rhs.org.uk/plants/360512/leymus-arenarius-blue-dune/details) · [Kansas State University](https://www.k-state.edu/turf/resources/ornamental-grasses/grasses/leymus-arenarius.html) ## Maintenance Cut dead foliage down in autumn and divide clumps from mid-spring to early autumn. Plan for rhizome spread at planting; use a suitable physical barrier or a site where expansion is acceptable. Kew accepts Leymus arenarius and lists Elymus arenarius as a synonym, so the catalog’s existing cultivar identity is retained. [RHS](https://www.rhs.org.uk/plants/360512/leymus-arenarius-blue-dune/details) · [Kew Science](https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:407309-1)