Festuca — Fescues
Ornamental blue fescue grasses have become a reliable accent in gardens, breaking up shades of green and inserting wispy texture in front of broad-leaved perennials and shrubs. Many popular fescues are European imports that tend to be short-lived and must be replaced frequently. All grasses in the Festuca genus are deer resistant.
Tight, low-growing clumps of Festuca glauca, common blue fescue—also called Festuca ovina glauca—rarely become larger than 1 ft. tall and wide and can be effectively interspersed as color accents against burgundy foliage and darker backgrounds. They are sometimes planted in broad drifts in geometric designs as a stylized groundcover, but after 1 or 2 years, plants often develop unattractive brown leaves or die out completely and must be replaced.
Longer-lived cultivars with more attractive forms, ‘Siskiyou Blue’ and ‘Elijah Blue’, are recommended as is the finer-textured species, Festuca amethystina. All readily self-sow. The blue fescues prefer morning sun only and thrive when protected from harsh afternoon summer sun and given adequate waterings.
More durable yet are the native fescues. Festuca idahoensis varies in coloration, as do some of the non-natives. Individual clumps may be purchased or seeded in shades of blue, gray, silver or green. Although this species is longer lived than other blue fescues, it also is best replaced after a few years. It is the only blue fescue that tolerates full sun.
Native to Sonoma County woodlands and throughout the Coast Ranges to Oregon, Festuca californica grows taller than the low, bluish tufts called blue fescues, although this more robust California fescue commonly has bluish green leaves. This grass is mid-sized with a fountain-like shape 1½-2 ft. tall and a bit wider. The flower stalks—violet tinged in spring and summer—rise up another foot or more and turn a tawny tan.
California fescue tolerates most soils and exposure to sun but is best in part shade where it grows naturally protected from harsh afternoon sun. With summer water in gardens, the arching blades remain vibrant and evergreen, but they also stay green in deep shade with little water as they do in the wild where they have survived for eons with no supplemental irrigation.
Festuca rubra, red fescue, is another useful native often planted as a lawn grass for shaded sites. It slowly creeps by underground rhizomes to create a dense turf and may be mixed with other grasses although it has finer textured blades than most.
Red fescue can also be planted as a low-maintenance groundcover and left unmowed to grow in loose clumps 4 to 12 in. high. It is particularly attractive on slopes where mowing is difficult. Of the many cultivars available, all vary in drought tolerance, color, and height. Most require moderate moisture.