Revegetation Program

(Excerpted from: Whitman Mission National Historic Site: General Management Plan, September 2000. U.S. Department of the Interior, National Park Service.)

In 1985, the park staff began a revegetation project with the objective to control non-native weeds that had invaded the park. Some of these plants were on the state and county noxious weed lists as targeted weeds for control and are still serious threats to local agriculture. The short term goal of the park staff was to establish healthy stands of grass to successfully compete with these weeds. The non-native grass species were chosen for the following reasons: the species had a good chance for success against the noxious weeds and the weed seeds still in the soil, and they would be similar in appearance to grasses that may have been growing there 150 years ago. Once these grasses were established, the park staff the would be able to gradually replace the non-native grasses with native species thought to be present during the Whitmans' time. This action is in concurrence with the 1984 Landscape Study and Management Alternatives for Revegetation: Whitman Mission National Historic Site which states that the overall goal for revegetation is to maintain the visual aspect of the historic period (USDI, 1984).

In 1989, the park staff established a native rye grass demonstration plot by the visitor center. It was planted in a native plant mixture of Magnar Great Basin wildrye (Leymus cinereus) and Sherman big bluegrass (Poa secunda). The Magnar Great Basin wildrye grows six to eight feet tall and the Sherman big bluegrass grows two to three feet tall. The bluegrass did not compete well and the entire area is gradually becoming Magnar Great Basin wildrye.

In 1987 and 1988, the 28 acre river oxbow and pasture area was planted with both native and non-native species to reproduce the historic scene. The native Magnar Great Basin wildrye was planted along with two species of non-native grasses, Reed canary grass (Phalaris arundinacea) and Alkar tall wheatgrass. The alkar tall wheatgrass (Elytrigia pontica) is the main grass in this area and grows to four feet tall. The Reed canary grass grows well on poorly drained soils.

Another native plant that has been discussed for possible use on the Mission Grounds is Sodar streambank wheatgrass (Elymus lanceolatus). This plant is a native, sod forming grass that grows six to eighteen inches tall. It grows on a variety of soils and can handle the dry conditions of summer.