Designing with Blue Grasses
by SCMG Steven Hightower
I love blue and gray foliaged plants because of the interesting contrast they provide when mixed with greens in the garden ranging from lime to dark forest. Echium, Artemesia, Senecio, and Lavendula 'Provence' all have a great look in the garden. Our Editor, Sara Malone, suggests that blue is also effective next to dark shades, such as maroon or brown/black.
Grasses is a loosely defined term that includes true grasses (Poaceae) and grass-like plants, including sedges (Cyperaceae), and rushes (Juncaceae), but we’ll refer to them all as grasses for our purposes. There are a few grasses that are distinctly blue in cast, and some that are more on the blue-green or gray-bluish side.
In recent years I’ve been experimenting with blue grasses as part of a larger interest in ornamental grasses. We’ve run several articles on ornamental grasses and lawn replacement, as that water-reduction technique is one of the primary uses for ornamental grasses. But design is another big reason: their mounding, tufted shapes, large and small, or undulating low swaths, if planted close together, add real distinction to the garden.
Larger blue grasses can stand individually or be mixed in with a range of other plants, some blue, some not. They can also be mixed together in sort of a tufted meadow—I have one area that combines blue fescue and blue oat grass with some other non-blue ornamental grasses.
Smaller blue grasses such as blue fescue or blue carex make a strong statement if planted fairly close in larger sweeps of color. And if you want to try that blue/dark combo, try placing Helictotrichon next to Phormium ‘Jack Sprat’ or the currently popular Black mondo grass Opiophogon nigrescens.
Here are a few blue grasses to try:
Festuca glauca (blue fescue) has to be the workhorse of the blue world. ‘Elijah Blue’, the most commonly found, is powder blue. ‘Boulder Blue’ is thought to be the bluest fescue and forms compact cascading mounds. Grow in full sun to light shade, and provide some supplemental water in summer.
Helictotrichon sempervirens (blue oat grass) is one of my favorites. It’s larger and more dramatic, with steel or powder blue foliage and spiky architecture. Full sun or partial shade, with some supplemental summer water, and well-drained soil. Tolerates sandy and infertile soils, but not clay. I grow it in mounds created atop our Sonoma Mountain clay.
One of the Idaho fescues Festuca idahoensis ‘Siskiyou blue’ is a spruce blue in color. A drought tolerant native, it has a bit more formal, upright habit and does well in sun or light shade.
Schizachyrium scoparium (little bluestem) ‘The Blues’ is bright, intense blue, fine and upright, turning to purple or burgundy in the fall. It’s a very low maintenance grass that likes full sun, not much extra water and no fertilizing, or its fluffy white seed plumes will droop.
Carex glauca (also c. flacca) (blue sedge) is blue-gray with narrow arching blades. Planted fairly close it will form an undulating low lawn. Takes full sun, but will also do well in dappled shade, or under trees and is fairly drought tolerant, requiring only occasional summer water.
Bouteloua gracilis 'Hachita' ('Hachita' blue grama grass) has narrow, blue-green leaves that form dense mounds. In summer, elongated “eyelash” seed heads add visual interest. This tough, drought-tolerant grass thrives in sand or clay soil with full-sun exposure. Once it grows together into a continuous sod, it can also be mowed once a month to create a soft, rolling lawn.
Lomandra confertifolia spp rubiginosa 'Seascape'. Grass-like Lomandra is tough as nails, and this is a very blue cultivar. Prefers full sun to part shade. Will tolerate frost and drought conditions. Virtually no care and doesn't get tatty like most grasses.
Also in the grass-like category, Dianella revoluta has 1-inch wide blue-green lance-shaped leaves. A couple of cultivars—‘Baby Bliss’ and ‘Little Rev’ are quite blue. Both are slowly spreading, compact clumps of bluish green that get around 18 inches in height. Plant Dianella in full sun to light shade. It requires low water, with only occasional soakings once established.