• GENERAL BOTANICAL CHARACTERISTICS
• RAUNKIAER LIFE FORM
• REGENERATION PROCESSES
• SITE CHARACTERISTICS
• SUCCESSIONAL STATUS
• SEASONAL DEVELOPMENT

GENERAL BOTANICAL CHARACTERISTICS:

Blue wildrye is an erect, rapidly developing, cool-season, native perennial bunchgrass [8,19,39,40]. It is short lived and drought tolerant [13,40,79]. Blue wildrye commonly grows in small tufts of only a few stems [40,90]. Bunches in the Pacific Northwest rarely exceed 4 inches (10 cm) in width [44]. Leaves grow up to 12 inches (30 cm) long and are chiefly cauline. The blades have a rather rough texture. Culms range in height from 1.9 to 5.9 feet (60-180 cm) and form small, mostly loose tufts [94]. The inflorescence is a dense, erect, narrow spike approximately 2.4 to 6.4 inches (6-16 cm) long. Spikelets are 2 or rarely 3 per node or solitary at the upper and lower nodes, and 2 to 4 flowered [94]. Seeds have an awn that is up to 0.75 inch (1.9 cm) long [72].

The vigorous, fibrous root system is well branched and penetrates deeply [47]. Blue wildrye may produce stolons [41], short rhizomes [35], or lack horizontal stems [43,79].

RAUNKIAER LIFE FORM:

Hemicryptophyte

REGENERATION PROCESSES:

Abundant seed is usually produced in California [79] and elsewhere. In a seedbank study in eastern Washington, blue wildrye was found to be the 6th most common viable plant species (out of a total of 57 viable species) in 4-inch (10 cm) deep soil samples collected from an intermediate-successional-stage ponderosa pine forest [73]. Data summarized by Fulbright and others [32] indicate that seeds have a germinative capacity of 80 to 85%. Seed stratification or scarification is not necessary for adequate germination. Ripe seeds collected in western Colorado in late summer were nondormant when tested within a few months, had high germination percentages under various photoperiods and thermoperiods, and germinated both unstratified and cold stratified [45]. Seeds remain viable for 2 to 4 years [32], but one study showed percentage germination of mature, cleaned seed stored at 59 to 86 degrees Fahrenheit (15-30 ^oC) dropped sharply after 2 years [59] .

Blue wildrye also regenerates via rhizomes [35,37,93], stolons [19,35], and tillering [19,72].

SITE CHARACTERISTICS:

Blue wildrye occurs from near sea level in California to subalpine montane sites throughout the Intermountain Region [4,19,44,90]. Within woodlands and conifer-dominated communities, blue wildrye is frequently associated with riparian areas [14,93,94,97]. In California it is present along montane meadow edges and on elevated flats where the water table falls well below the soil surface through the growing season [38]. Within big bluestem (Andropogon gerardii var. gerardii) communities in western North Dakota, this species is usually located on the lower portions of steep slopes where sites receive water runoff [39].

Soils: Blue wildrye grows best on moderately moist soils [47,79,90]. Sites are characterized by low fertility and well-drained soils, with textures ranging from clayey loam to sandy loam [8,40]. Plants are moderately sensitive to saline soils and are not tolerant of shallow soils [40,71].

Hassell and others [40] listed the following range of environmental adaptation for blue wildrye on mountain sites in the Intermountain Region:

Minimum mean annual precipitation       >16 inches
Minimum winter temperature              -40oF
Inundation during spring runoff (EST)   21-35 days
Ability to grow on shallow soils        poor
Heat tolerance                          good

from sea level to 10,500 feet (0-3,200 m) in CA [68]    
6,300 to 11,000 feet (1,921-3,354 m) in CO
4,200 to  8,000 feet (1,280-2,439 m) in MT [27]
2,500 to  5,700 feet (762 to 1,738 m) in OR [37]
4,297 to 10,496 feet (1,310-3,200 m) in UT [94]
5,400 to 10,500 feet (1,280-2,439 m) in WY [27]

SUCCESSIONAL STATUS:

Blue wildrye is typically favored by disturbance [3,31,54,72,90]. On sites in the Pacific Northwest, plants are often locally abundant on old burns and cutover areas [64,90]. Other common sites include avalanche chutes, woodland openings, prairies, and "dry" wetlands [17,37,44,90]. It is a common early seral component of both nonforested and forested communities throughout the central Rocky Mountain region. While sometimes locally abundant, this shade tolerant bunchgrass rarely forms dense, pure stands [79,90,92,94]. Plants are apparently favored by disturbances such as burning and logging [3,54,90,87]. Merrill and others [62] report this species in early successional stands in the Mount St. Helens volcanic blast zone. Although blue wildrye rapidly establishes and increases under early seral conditions, numbers may decline dramatically after 3 to 4 years without further disturbance [31,40].

A Colorado succession study in 25 high-elevation quaking aspen stands, 1st conducted in 1964 and repeated in 1994, showed a marked increase in blue wildrye cover over 30 years. The increase was concurrent with a shift in the number of quaking aspen trees towards fewer, larger trees without a change in total basal area. Most other understory species remained constant. Over the 30-year period livestock grazing was limited or nonexistent on the study sites [18].

In a postfire succession study spanning 17 years in Grand Teton National Park, Wyoming, blue wildrye was rare in unburned subalpine fir-Engelmann spruce-lodgepole pine (Abies lasiocarpa-Picea engelmannii-Pinus contorta) forest, but began appearing in adjacent severely burned areas within 2 years after fire, reaching greater than 5% cover. [28].

In a California old-field succession study where a cultivated field surrounded by foothill woodland was abandoned in 1937 then studied until 1966, blue wildrye was present in 1944 and 1951 but was less abundant by 1951. It was not found in 1966, although it was present in adjacent blue oak (Quercus douglasii)/chamise (Adenostoma fasciculatum) woodland sampled in 1963 [95].

In an Oregon riparian ponderosa pine community where livestock were excluded for 10 years, blue wildrye increased significantly (P<0.01), from 0 to 48% frequency [36].

SEASONAL DEVELOPMENT:

Blue wildrye produces good growth during the cool part of the grazing season in California; seed ripens in early July in the foothills and in late August at higher elevations [47]. Anthesis data for several western states are presented below [27]:

State     Earliest flowering     Latest flowering

CO        June                   August
MT        June                   August
ND        July                   August
UT        June                   August
WY        July                   August

Related categories for Elymus glaucus | Blue Wildrye