Southeastern Wisconsin Invasive Species Consortium, Inc.


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Lyme Grass

Lyme Grass

Lyme Grass
Genus: Leymus
Species: arenarius

Also known as sand rye grass, wild rye, blue lyme grass, and blue dune.


This perennial grass can grow to 2-4 feet in height. Each evergreen leaf is blue-green in color and about 12 inches long and 1/2 inch wide. Flowers are dense spikes that are blue-green in early summer and turn beige later in the year.


The blue leaves stand out clearly among the green leaves of the native American dune grass (Ammophila breviligulata). Lyme grass also has bigger seeds, tougher blades and stiffer seed stalk. This grass may also be confused with Elytrigia dasystachya, a subspecies of which is the state-threatened thick-spike wheatgrass. Lyme grass has wider leaves, greater then 1/16 of an inch, while the native’s leaves are smaller then 1/16 of an inch and curl inward to appear much smaller.

Impacts & Habitat

This plant is an ornamental grass native to Europe and Asia. It spreads primarily by underground stems (rhizomes), but also reproduces by seed.

This grass can grow in most habitats, although it prefers well-drained sandy soil and full sun. It can handle extremes of heat and cold, and it is drought resistant. This plant is sold as an ornamental, and is used to control erosion. However, it can quickly become invasive on dunes. Of particular concern in the Great Lakes area is its ability to stabilize naturally shifting sand dunes of the Great Lakes.


Mechanical removal is not effective because new plants sprout from rhizomes and root fragments left in the soil. Treating the stems with a glyphosate solution in early spring before other native species emerge is effective. Grass specific herbicides can be used but will also kill native grasses. Repeated applications may be necessary to kill all plants.