Bluebunch Wheatgrass

Bluebunch wheatgrass is an important species found in southern BC grasslands. Suitable for grassland restoration and site rehabilitation where there is native plant community objective, however it may be difficult to establish.

General Description:

Bluebunch wheatgrass is a native, perennial, cool season bunchgrass with fibrous roots, sometimes forming clumps as wide as 150 cm (59 in.). Stems range from 60 to130 cm (24 to 51 in.) tall, with narrow leaves mostly originating from the stem.

Bluebunch wheatgrass reproduces primarily through seed, but may reproduce vegetatively with short rhizomes on wetter sites. Bluebunch wheatgrass is an important species in British Columbia grasslands, occurring mostly in the south, central, and southeast parts of the province. It has historical importance in the development of the livestock industry in British Columbia because of its value for fall and winter grazing. It is also an important indicator of good ecological condition.

There are two recognized forms or subspecies of bluebunch wheatgrass. The smooth or awnless form (Pseudoroegneria spicata ssp. inermis) is more common in British Columbia, although the awned form (Pseudoroegneria spicata ssp. spicata) is also found. These two subspecies differ by only one gene, and there is some question whether this merits the distinction of the two subspecies.

Origin:

Native to British Columbia

Distribution:

Found in a wide range of habitats throughout the province, but is common only in the southern interior regions.

Habitat and climate:

Occurs in dry, in open areas, on rocky slopes, and in forest openings.

Uses:

As an important native component in B.C. grasslands, bluebunch wheatgrass is an important species for consideration in reclamation and restoration. It provides valuable forage for wildlife and all types of livestock.

Optimal time of grazing use:

Bluebunch wheatgrass can support grazing in all seasons. Sufficient growth should be allowed before grazing bluebunch wheatgrass in the spring. At least 15 cm (6 in.) of growth or allowing plants to reach the 4-leaf stage of development is recommended. Spring use should be deferred, or alternated to fall use every 2-3 years. New stands should be well established (2-3 growing seasons) before grazing is allowed.

Recovery after use (rating):

Recovery after use:

Repeated defoliation during the spring growth period is likely to reduce plant vigour, and lead to plant mortality (see McLean and Wikeem 1985). Suitable regrowth is likely to occur with late summer or fall rain if proper utilization (40-50% of growth) is applied in the spring season.

Forage yield (rating):

Forage yield:

Forage yield will vary depending on the location and composition of the stand. McLean and Bawtree (1982) reported a yield of 660 kg/ha (589 lb/acre) in a mixed native stand (with needle-and-thread grass) on a mid-elevation (850 m) (2,789 ft.) site near Kamloops, B.C.

Palatability/Nutritional Value:

Bluebunch wheatgrass is highly palatable to livestock and wildlife and provides good winter forage when rested during the growing season. Plants remain green well into summer. Crude protein of green leaf material sampled in May was 15%, and cured material sampled in November was 3% in the Kamloops area (McLean and Bawtree 1982).

Longevity (rating):

Longevity:

Bluebunch wheatgrass is long lived.

Persistence (rating):

Persistence:

Bluebunch wheatgrass has good persistence once established and managed appropriately.

Invasiveness (rating):

Invasiveness:

Bluebunch wheatgrass is not invasive, but can spread into adjoining communities on sites where it is well adapted.

Competitiveness (rating):

Competitiveness:

Bluebunch wheatgrass is considered to be reasonably competitive when it is well established in naturally occurring native plant communities.

Weed resistance (rating):

Weed resistance:

Bluebunch wheatgrass has low weed resistance when it is being established. Cheatgrass infestations can inhibit establishment on some sites. Established stands have higher weed resistance but can be susceptible to highly invasive species.

Erosion control (rating):

Erosion control:

Bluebunch wheatgrass can provide some erosion control on dry, disturbed sites where native vegetation is desired.

Drought tolerance (rating):

Drought tolerance:

Bluebunch wheatgrass is very drought tolerant.

Winter hardiness (rating):

Winter hardiness:

Bluebunch wheatgrass is cold tolerant.

Soil texture preference (rating):

Soil texture preference:

Bluebunch wheatgrass does best on medium-coarse textured soils, but also can be found on heavy- to medium- to coarse-textured soils.

Flooding tolerance (rating):

Flooding tolerance:

Bluebunch wheatgrass is not tolerant of high water tables, saturated soils, or flooding.

Salinity tolerance (rating):

Salinity tolerance:

Bluebunch wheatgrass will tolerate weakly saline conditions.

Acidity tolerance (rating):

Acidity tolerance :

Bluebunch wheatgrass does not grow on highly acidic sites.

Shade tolerance:

Bluebunch wheatgrass can tolerate some shade.

Fire tolerance (rating):

Pests and/or disease threats:

Grasshoppers and other insects may damage stands.

Ease of establishment (rating):

Ease of establishment:

Bluebunch wheatgrass is more difficult to establish than other native wheatgrasses. The viability of commercially available cultivars is questioned by some professionals, and locally collected seed is often used when maintenance of ecological integrity is desired. Whitmar was the first commercially available variety. It was selected from the awnless subspecies in the Palouse grasslands near Colton, Washington, in 1946. It was selected for forage production, seedling vigor and seed production and is best suited for areas with more than 300 mm (12 in.) of annual precipitation. “Goldar” was released in 1989 and developed from an awned collection originating from a ponderosa pine woodland on the Umatilla National Forest near Anatone, Washington. A more recent (2001) awned variety called P-7 was created in an effort to increase adaptability using open pollination of 25 different populations from various states, including one from the Slocan Valley of British Columbia. There is little information on its full range of adaptation but it is expected to perform better under drier conditions than the older varieties. Anatone, released in 2003, is similar to Goldar but expected to establish and perform better in areas with 250 to 300 mm (10 to 12 in.) of precipitation. Secar, a variety released in 1980, was promoted as bluebunch wheatgrass, but originated from a misidentified population from the Snake River Valley in Idaho and is now known as Snake River wheatgrass (Elymus wawawaeinsis). This variety is suited to lower precipitation areas 200 mm (8 in.). Discovery, another Snake River wheatgrass (not known to occur naturally in British Columbia), was released in 2008.

Application requirements:

Seedbed preparation followed by drill seeding at depths of 0.6 to 1.27 cm (1/4 to 1/2 in.) produce the best results, but this method is likely to be unsuited to most projects and site conditions found in British Columbia. When seeded in pure stands, a seeding rate 260 PLS (pure live seed) per square metre (24 PLS per square foot) is recommended. Broadcast seeding is likely to be more applicable, but establishment may be slow and results mixed. Some B.C. restoration practitioners have used vegetative or plug plantings. Broadcast seeding rates for pure stands should be 150-200% of the drilled seeding rate. Hay seeding using locally sourced plant materials was applied with marginal results on a restoration project in the South Okanagan.

Suggested mixtures:

Bluebunch wheatgrass should be seeded with other suitable native species, rather than with more competitive introduced species.

Management considerations:

Bluebunch wheatgrass does not tolerate heavy, continuous grazing. A rest or deferred rotation grazing system is recommended to keep this grass in a healthy and vigorous condition.