What's the best grass mixture for an eastern Oregon lawn?

Last Updated: 
August 4, 2008

CORVALLIS - Lawns in eastern and southern Oregon may not thrive if planted with grass mixes developed for the Willamette Valley. Each site, and each owner, will have different requirements and expectations.

Despite the variables, Tom Cook, turf specialist at Oregon State University, says there are a few mixes that will meet the most common needs of homeowners east of the Cascades. He has outlined them in his publication, "Practical Lawn Establishment and Renovation" (EC 1550), published by the OSU Extension Service and available on line at: http://extension.oregonstate.edu/catalog/pdf/EC/EC1550.pdf

"You have to be flexible in shopping for grass seed, because each mix will be a bit different," said Cook. "The key is to study the label and go for the contents, not the price or the hype."

Below are just a few grass seed mixtures that Cook recommends for eastern and southern Oregon lawns.

For general turf on sunny sites, try a mix of 75 percent Kentucky bluegrass and 25 percent fine fescue, which makes a fine lawn where there is sun and areas of light shade.

"To look its best, this lawn requires regular irrigation, medium to high nitrogen fertilization and regular mowing," explained Cook. "Unless fertility is very low, the bluegrass will dominate this mixture quickly and may become susceptible to necrotic ring spot disease. Keep in mind that bluegrass-fine fescue mixes are heavy thatch producers, so annual or every other year dethatching will be required to keep these lawns in good shape."

Another choice for sunny areas is 50 percent perennial ryegrass, 25 percent Kentucky bluegrass and 25 percent fine fescue.

"This mix will establish quickly into a rugged lawn," he said. "With less Kentucky bluegrass in the mix, it may be less susceptible to necrotic ring spot than the previous mix. Its requirements are about the same as above, although ryegrass cuts harder than bluegrass, so keep your mower blade sharp."

Also good in sun is 100 percent tall fescue (turf types only).

"This should be a popular choice for hot areas such as La Grande and Medford," said Cook. "It provides a deep-rooted, rugged turf that can go two or three weeks between deep waterings. An added bonus is that this mix does not produce much thatch."

Tall fescue tolerates shade as well as full sun, and newer varieties are only slightly coarser in texture than coarse Kentucky bluegrass, he said.

For general turf on shady sites in eastern Oregon, Cook recommends a 50 to 75 percent fine fescue with 25 to 50 percent Kentucky bluegrass. This mixture should be mown relatively tall (two to two-and-a-half inches), kept fertile in the medium range and watered only as needed.

For more information on home lawn care, check out these publications from the OSU Extension Service on line.

  • Fertilizing Lawns (EC 1278) (recently revised)
  • Necrotic Ring Spot on Turf in Oregon (EC 1462)
  • Conserving Water in the Garden: Landscape and Lawn Care (EC 1531)
  • Controlling Moss in Lawns (FS 55)
  • Maintaining a Healthy Lawn in Western Oregon (EC 1521)
  • If you don't have access to the web, write for a catalog and order form for printed versions of these publications from: Publication Orders, Extension and Experiment Station Communications, OSU, 422 Kerr Administration Bldg., Corvallis, OR 97331-2119. Or call 1-800-561-6719 and request a catalog.

    Author: Carol Savonen
    Source: Tom Cook