Idaho Fescue…native to the Blue Mountains

Idaho Fescue, Festuca idahoensis, is a beautiful blue-green, perennial bunchgrass, native to the intermountain regions of the western United States. It once dominated much of Oregon, Washington, and Idaho. It grows naturally without irrigation in areas of 10-20 inches of precipitation. Established stands are usually free of diseases and insect pests, and effectively limit the introduction of weeds.

  • Origin: This Idaho fescue was collected from native plants growing at 3000 ft. elev., near La Grande, OR. It was increased at the GROWISER native plant preserve near Summerville, then grown commercially in the Grande Ronde Valley.

  • Size: Plant size depends upon soil depth and moisture. Mature bunches are about 12 inches tall and 6 inches in diameter, before flowering. After flowering, the plants may reach 30 inches in height.

  • Uses: Idaho fescue is the premier native bunchgrass for land restoration. It has very fine leaves that provide excellent forage for wildlife. Its extensive fibrous root system enables it to withstand drought, prevent soil erosion, and out-compete annual grasses such as cheatgrass and medusahead.

  • Urban landscapes: The deep turquoise color of this species makes it particularly attractive for low maintenance flower gardens. Plants may be used individually or in large natural areas. Solid stands may be used as lawns and mowed a few times per year, but no closer that 3- 4 inches in height. After establishment, Idaho fescue grows all summer without watering.

  • Establishment: Idaho fescue's seed is very small and produces weak seedlings, so removal of competition before seeding is essential. If perennial grasses are present on the site, they must be entirely killed before Idaho fescue can be successfully established. That usually takes two full years. It is recommended to kill the grasses with two applications of glyphosate, 1-2% solution. Plow or deep-till the soil, after the grasses have been killed. The second year, fallow the soil and till, to kill all germinating weed seeds and break down soil clods.

  • Seeding: In April of the third year, as soon as the soil is dry enough to drive on without compaction, spray the new weed seedlings again with glyphosate. To stimulate germination, broadcast 100 pounds of 16-16-16 fertilizer per acre. Sow 3-10 pounds of Idaho fescue seed per acre, depending upon the desired use. The seed may be either broadcast or planted with a grain drill. Mixing with wood pellets, 2:1 pellets to seed, extends to seed and greatly helps it flow through the seeder. If it was broadcast, lightly harrow to incorporated the seed. Finally use a heavy roller to firm the seed with the soil.

  • Weed control: Even with the best soil preparation, some weeds will germinate after seeding. Remove them by hand, mow then before they seed, or ask your local chemical dealer about herbicides for particular weeds in fine fescue fields.

  • Grazing or mowing: Idaho fescue should not be grazed or mowed until early July, when the seed heads have formed. Then, unless it is to be harvested for seed, it should be grazed or mowed, but no closer than 3-4 inches above the ground. It should not be grazed or mowed after mid-September, when fall regrowth begins. That will ensure vigorous growth in the spring. Such a stand of Idaho fescue will last indefinitely.

  • More information: To see Idaho fescue growing, contact Andy Huber at GROWISER, (541)-962-1512 or ahuber@eou.edu