Grass family (Poaceae)
Description: This introduced perennial grass is about 1-2' tall, consisting of a small tuft of culms with 5-6 alternate leaves. The culms are green or grayish blue, hairless, flattened, and unbranched. The leaf blades are up to 4" long and 4.5 mm. across; they are grayish blue, hairless or sparsely canescent, and flat or slightly twisted. The tip of each blade is keel-shaped. The leaf sheaths are grayish blue or dull green, somewhat flattened, hairless or sparsely canescent, and shorter than the internodes (the length between adjacent nodes on the culm). Each ligule consists of a papery membrane, while the nodes are narrow, light to medium green, and slightly swollen. Each culm terminates in a rather sparse panicle of spikelets about 2-5" long and 1-2" across. Individual or whorls of 2-3 branches occur along the rachis (central stalk) of the panicle; these branches are more or less ascending and longest toward the middle of the panicle. Some spikelets are located near the rachis (central stalk). Each spikelet is about 4-5 mm. long, 1.5 mm. across, and flattened; it consists of a pair of glumes and 4-5 lemmas with florets that are organized into 2 columnar ranks. Disarticulation is above the glumes. The glumes are 1.62.5 mm. in length (one glume is a little longer than the other); they are oblong-lanceolate, curved along the keel, greyish blue, and membranous along their margins. The lemmas are 2.02.5 mm. long, oblong-lanceolate, curved along the keel, light to medium green, and membranous along their margins. Each lemma has a line of fine hairs along the lower half of each vein (midvein & two lateral veins) and a sparse web of fine hairs at its base (these hairs are sometimes absent or difficult to see). The blooming period occurs during the summer. Pollination is by wind. The entire inflorescence becomes tan as the grains ripen. The root system is fibrous and rhizomatous.
Cultivation: The preference is full or partial sun, mesic to dry conditions, and poor soil containing too much sand, rocky material, or clay.
Range & Habitat: This common grass occurs in every county of Illinois (see Distribution Map). In spite of the common name, this species is native to Eurasia. Habitats include dry rocky woodlands, openings in upland woodlands, upland prairies and sand prairies, savannas and sandy savannas, areas along railroads and roadsides, weedy meadows, pastures, and waste areas. Canada Bluegrass was originally introduced as a source of forage for dry pastures with poor soil. It has since spread into other areas.
Faunal Associations: Many insects feed on various parts of the perennial Poa spp. (Bluegrasses). These include various grasshoppers, plant bugs, stink bugs, skipper caterpillars, moth caterpillars, leaf beetles, beetle grubs, and others (see Insect Table for a listing of these species). Both upland gamebirds and granivorous songbirds eat the seeds of bluegrasses, including the Mourning Dove, Ring-Necked Pheasant, Prairie Chicken, Wild Turkey, House Sparrow, and Field Sparrow. The foliage is a source of food for rabbits and voles. It is also palatable to livestock.
Photographic Location: An upland opening at Busey Woods in Urbana, Illinois.
Comments: Canada Bluegrass can be distinguished from other Poa spp. (Bluegrasses) by its flattened culms and grayish blue or blue-green foliage. Also, its panicle of spikelets has a more narrow shape than many other bluegrasses. Another common species, Poa pratensis (Kentucky Bluegrass), prefers ground that is more moist, loamy, and fertile. Unlike Canada Bluegrass, it has terete culms (round in cross-section) and green foliage.