Sideoats Grama is a perennial of dry woods and prairies. It is a warm-season grass that grows from scaly rhizomes. It is the largest and most coarse of the grama grasses, with stems (culms) growing from 1 to 3.5 feet high.
Leaves: The blade color is bluish green, with a purplish cast in the spring, maturing to a reddish-brown or straw color in the fall. Leaf blades are coarse, straight and mostly basal up to 20 inches long. Smaller leaves appear sparsely on the flowering spikes and these are much shorter. Both surfaces of the leaves have forward projecting stiff hairs such that the leaf feels smooth when swiped from base to tip but very coarse in the reverse direction.
The leaf sheath is round, split, can be smooth or with long spreading hair near the upper part of the sheath and also on the lower part of the leaf blade margins. The ligule may also have fine hair and is thin and translucent.
The inflorescence is a spike like panicle held above the leaves. These can vary greatly in number per plant with each spike containing ten to forty-five short drooping spikelet branches that hang mainly from one side of the stem in two rows and drop off at maturity (disarticulate) leaving a zig-zag stem. The panicle spikes will bend over with their weight as the spikelets mature.
Each spikelet branch can have 3 to 7 or 9 very crowded spikelet clusters with each spikelet having one lower bisexual floret and 1 or 2 sterile and rudimentary florets. The lowest lemma is 3-veined with the veins usually extending as short awns. The stamens are reddish when shedding pollen, but can also be yellow to orange.
Habitat: Sideoats Grama does not tolerate shading by taller grasses. It is an important range grass as it begins growth early in the spring and while the leaves will curl in the heat of summer and become a whitish-brown, it has another period of green growth in the fall and grows up to an altitude of 7,000 feet. It works as a home ornamental grass as it is hardy up into USDA Zone 2b and is tolerant of dry and hot locations. Fall color is a yellowish-brown. For ornamental purposes, in habitats where the summer temperature is more moderate and moisture is adequate, this can be a good plant, especially colorful during flowering. Give it some room as the panicle branches like to spread.
Names: The genus Bouteloua is an honorary for Claudio and Esteban Bouteloua, 19th century Spanish botanists who studied grasses in the new world. The species curtipendula is from the Latin meaning 'short hanging', as in the short-stalked grain heads. The author names for the plant classification are ‘Michx.’ which is for Andre Michaux (1746-1802), French botanist who made many exploring expeditions in the U.S. collecting and cataloging many species. His work was furthered by ‘Torr.’ who is John Torrey (1796-1873), American botanist, who among many things, taught Asa Gray, contributed to the early parts of Flora of North America and who published the reports of plants collected by John C. Fremont’s 1843-1844 Exploring Expedition to the Rocky Mountains.
Above: The tall developing panicle is held well above the leaves with spikelet branches drooping to one side in two rows. Panicle stems are upright but toward maturity the panicle will bend over. Drawing by Agnes Chase from Norman C. Fassett's Grasses of Wisconsin
Below: 1st photo - The blade veins are prominent. Surface and edge have forward projection hairs giving a rough feel in a downward direction. 2nd & 3rd photos - The leaf collar is often yellowish green to brown with a few hair at the throat, on the upper part of the split sheath and the lower blade margins.
Below: 1st photo - The collar may also have hair at the throat. 2nd photo - Individual branches off the central rachis can have 3 to 9 crowded spikelets. Each spikelet has 1 fertile and 1 or 2 non-fertile florets.
Below: 1st photo - The tall developing panicle. 2nd photo - Note the reddish color on the anthers as the pollen is shed.
LBelow: Mature spikelets in Autumn. The short awns are formed from the veins of the lower lemma.
Below: Each spikelet containing drooping branch can have 3 to 7 or 9 very crowded spikelet clusters
Below: Plants just as flowering is about to begin.
Notes: Sideoats Grama is not indigenous to the Garden site. It was introduced to the Garden by Eloise Butler on Aug. 27, 1912 with plants she obtained in Columbia Heights, MN.
Sideoats Grama is a native North American plant, found all but six of the lower 48 states and also in the lower Canadian Provinces. It is considered threatened or endangered in six states, Michigan being the closest to Minnesota. In Minnesota it occurs throughout the state except in the NE quadrant.
There are three species of Bouteloua native to Minnesota: B. curtipendula, Side-oats Grama; B. gracilis, Blue Grama; and B. hirsuta, Hairy Grama.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"