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TREES & plants

Blue lyme grass

Blue lyme grass.

Blue lyme grass is an attractive blue-leaved grass, but it should be used with caution.  This is a running grass with aggressive tendencies.  It has been classified as invasive in Wisconsin, especially in areas that border Lake Michigan. Also known as Elymus arenarius.

This plant has some cultivated varieties. Go to list of cultivars.

Botanical name: 
Leymus arenarius
All Common Names: 
Blue lyme grass, European dune grass, sand wild rye
Family (English): 
Grass
Family (Botanic): 
Poaceae
Tree or Plant Type: 
  • Grass, 
  • Perennial
Native Locale: 
  • Non-native
Landscape Uses: 
  • Container, 
  • Massing
Size Range: 
  • Large plant (more than 24 inches)
Light Exposure: 
  • Full sun (6 hrs direct light daily), 
  • Partial sun/shade (4-6 hrs light daily)
Hardiness Zones: 
  • Zone 4, 
  • Zone 5 (Chicago), 
  • Zone 6, 
  • Zone 7, 
  • Zone 8, 
  • Zone 9, 
  • Zone 10
Soil Preference: 
  • Moist, well-drained soil
Season of Interest: 
  • Early summer, 
  • Mid summer, 
  • Late summer, 
  • Early fall
Flower Color & Fragrance: 
  • Other
Shape or Form: 
  • Arching
More Information: 

Size and Form

Blue lyme grass potentially can grow to 3 feet tall, but the habit is often floppy, making it appear shorter.

Plant Care

Blue lyme grass prefers full sun or light shade and can tolerate a wide range of soil conditions.  It is salt tolerant

This is a cool season grass, so its most active growth occurs in spring and fall.  In cold regions, it will be completely dormant instead of semi-evergreen in winter.

Blue lyme grass may be mowed down in fall or late winter.

Disease, pests, and problems

No serious pest problems.

This plant can be an aggressive grower as it is a running grass, spreading by rhizomes.  It is considered invasive in Wisconsin.

Native geographic location and habitat

Native to Europe.

Leaf description

Leaves are about 1/2 inch wide and up to 18 inches long.  They have a distinct blue to blue-gray color.  The leaves may briefly change to yellow before going dormant.

Flower description

Flowering occurs in mid-summer.  Tiny flowers are produced in a blue-green spike.

Fruit description

The small fruit (caryopsis or grains) are held in a narrow spike that matures to beige.  Not very showy.

Cultivars and their differences

Blue Dune  (Leymus arenarius 'Blue Dune'):  A more heat tolerant cultivar.

Leymus arenarius or Blue lyme grass

We do not seem to have this in our living collection.