Bluejoint Grass
Calamagrostis canadensis
Grass family (Poaceae)

Description: This perennial grass forms dense stands or tufted culms that are 2-5' tall. In areas where this species is more sparsely distributed, it resembles a bunchgrass, while in other areas where it is dominant, this grass forms a coarse sod. Both fertile and sterile shoots are produced. The culms are light green or straw-colored (stramineus), terete, glabrous, hollow, and unbranched. There are 5-10 alternate leaves along the entire length of each culm. The leaf blades are 4-12" long, 4-8 mm. across, and linear in shape; they tend to be widest toward the middle or lower middle. The leaf blades are ascending to widely spreading and rather floppy. The upper and lower surfaces of the leaf blades are pale green, medium green, or blue-green; they are glabrous and sometimes slightly glaucous. The leaf sheaths are pale green, longitudinally veined, glabrous, and open; they are shorter than the internodes. The ligules are white-membranous and 2-4 mm. in length; sometimes the leaves become loose at their ligules. The nodes are slightly swollen, glabrous, and dark-colored. Fertile culms terminate in panicles of single-flowered spikelets (one panicle per culm). The peduncles of these panicles are about 6-12" long. The panicles are 4-10" long and up to one-half as much across. Depending on their stage of development and the variety of this grass, these panicles can be open, loose, and narrowly pyramidal in shape (as occurs during the blooming period, particularly with var. canadensis), or they can be rather dense and contracted (as occurs before or after the blooming period, particularly with var. macouniana). The lateral branches of the panicle are up to 3" long and they can be either erect, ascending, or widely spreading below. These lateral branches subdivide into shorter secondary and tertiary branches that terminate in pale green to purplish spikelets. These branches are straight to slightly curved, but not wiry. Each spikelet has a pair of glumes, a lemma, and a floret. Depending on the variety of this grass, these spikelets vary in their size; the spikelets of var. canadensis are 3-4 mm. in length, while the spikelets of var. macouniana are 2-2.5 mm. in length. There is also a third variety, var. langsdorfi, that has spikelets 4.5-6 mm. in length, but it has not been found in Illinois thus far. The glumes are the same length as the spikelets; they are narrowly lanceolate in shape, glabrous, and convex to slightly keeled along their outer surfaces. The lemmas are slightly shorter than the glumes by up to 0.5 mm.; they are narrowly lanceolate in shape, glabrous, convex along their outer surfaces, and translucent toward their tips. Each lemma also has a tuft of white hair at its base and a delicate straight awn that extends from below the middle of the lemma to as high as its tip. The tufted hairs are the same length as the lemma or less, while extending in different directions. Each floret has 3 stamens and a pair of feathery stigmata. The blooming period occurs from early to mid-summer, lasting about 1-2 weeks for a colony of plants. The florets are cross-pollinated by the wind. Afterwards, the panicles and their spikelets become straw-colored during late summer, when the grains become mature. The tufted lemmas and their grains are dispersed by wind or water. Depending on the variety of this grass, the grains vary in size from 1.25-2 mm. in length; they are narrowly ellipsoid-oblongoid, light brown, glabrous, and very light in weight. The root system is fibrous and rhizomatous. Clonal offsets develop from the rhizomes. This grass occasionally forms large colonies at favorable sites.

The preference is full or partial sun, wet to moist conditions, and cool to warm summer temperatures. This grass adapts to a variety of soil types, including loam, clay, silt, sand, or some combination of the preceding types. It also has a broad pH tolerance. Standing water is tolerated by this grass if it doesn't persist throughout the growing season. Winter-hardiness is excellent. At some locations, this grass may spread aggressively. It is more easily established by division of its rhizomes, as the small seedlings are delicate.

Range & Habitat: The native Bluejoint Grass is occasional in the northern two-thirds of Illinois, becoming rare or absent in the southern section of the state (see Distribution Map). It tends to become more common northward. Habitats include wet to moist prairies, wet to moist sand prairies, wet to moist dolomite prairies, prairie swales, sedge meadows, marshes, bogs, fens, sandy pannes near Lake Michigan, swamps, and poorly drained areas along railroads. In some of these habitats, Bluejoint Grass may be the dominant or codominant ground vegetation. Unfortunately, many of the wetlands where this grass once occurred in great abundance have been destroyed, although it is still occurs in smaller stands at scattered locations.

Faunal Associations:
Insects that feed, or probably feed, on Bluejoint Grass and other Calamagrostis spp. include the plant bug Collaria meilleurii, the aphids Atheroides serrulatus and Sitobion beiquei, the leafhoppers Hecalus major and Cribrus shingwauki, and Orchellimum delicatum (Delicate Meadow Katydid). Bluejoint Grass has been used as a source of forage and hay for cattle and horses, and it is also eaten by the American Bison and elk. It is more palatable during the spring before the seedheads develop. The roots and lower stems of this grass are eaten by muskrats to a minor extent (Hamerstrom & Blake, 1939). Because this grass often forms colonies and it is fairly tall, it provides nesting habitat for many wetland birds and good cover for small mammals, snakes, birds, and other wildlife.

Photographic Location: A restored prairie at Meadowbrook Park in Urbana, Illinois. The photographed grass is Calamagrostis canadensis macouniana.

This wetland grass is distinguished by glumes that are slightly longer than the lemmas, tufts of hair at the bases of the lemmas, unbranched stems, and its medium-large size. The leaf blades are often bluish green. Bluejoint Grass resembles Reed Canary Grass (Phalaris arundinacea) somewhat, but it is smaller in size and less coarse. Bluejoint Grass also resembles Muhlenbergia frondosa (Common Satin Grass), but it is larger in size and its stems are unbranched. It is perhaps at its most attractive when the seedheads become light tan during mid- to late summer. It is also more conspicuous at this time of year, especially when clonal colonies develop from the rhizomes. Across its range, Bluejoint Grass is variable in the size of its spikelets. The typical variety (var. canadensis) has spikelets 3-4 mm. long, var. macouniana has spikelets 2-2.5 mm. long, and var. langsdorfi has spikelets 4.5-6 mm. long. Of these varieties, the typical variety is more common in Illinois, while var. macouniana is considered rare. The variety with the largest spikelets, var. langsdorfi, has not been reported from the state so far.