Bitter Panicgrass

Panicum amarum, commonly known as bitter panicum, bitter panicgrass, bitter switch grass or running beachgrass, is a perennial, warm-season dune grass native to coastal regions along the Gulf Coast of the United States and northeastern Mexico.Several subspecies occur along the US Atlantic coast as far north as Connecticut and Rhode Island; one of these, P. a. amarum, is native and state-listed as threatened.Panicum amarum is also found in the lower Midwestern US and been introduced to inland locations in North Carolina, West Virginia and New Mexico, the Bahamas and Cuba.

Bitter panicum grows in robust clumps, with thick, smooth, bluish leaves up to 50 cm (20 inches) long.Relatively long-lived (20+ years), P. amarum reaches a maximum stem height of about 2.5 meters (7.5 feet) at maturity, and grows variously upright or close to the ground (prostate).Blooming in late summer and fall, it produces clusters of low quality seed, but it reproduces mostly by vegetative sprouting along underground rhizomes.

In its native range, bitter panicum grows on coastal dunes, usually in the foredune slopes (closest to the ocean) where windblown sand accumulates.Tolerant of the harsh features of this environment: salt spray, inundation, storm surges, burial by drifting sand such that almost none of the plant is exposed, and high temperatures, it is one of the first colonizers in dune ecosystems.While P. amarum favors these exposed environments, it also thrives in fertile and moist soils, so it is found not just on the forefronts of sand dunes, but also on dune crests, interdunal swales, overwash sands, wet sandy soils, low fertility soils, and swamp margins.Most of its growth takes place in summer months, and it can suvive temperatures down to -18oF (-28oC).

Bitter panicum has a deep, extensive root and rhizome system that stabilizes sand from drifting from below, while its above ground vegetation prevents sand from being blown away. It is commonly used for dune stabilization projects as well as re-vegetation projects along roadways and mine sites to prevent erosion.A source of fodder for livestock, it is a reasonably palatable protein source for cattle, sheep and goats.Its dense growth is valuable cover and habitat for birds, waterfowl and small mammals.Native Americans made a tea infusion with the blades to reduce fevers and other ailments and the Cherokee used it to line the insides of moccasins.Several strains can be found in for purchase in nurseries; bitter panicum can be grown fairly easily as fresh rooted shoots or as rooted or unrooted stems.An ornamental variety, the “Dewey Blue” is a popular ornamental cultivar described as having a fountain-like profile and is often used for garden accents, borders, and dry or low-nutrient soil or difficult areas (e.g. along railroads).This cultivar was developed from a colony in Dewey, Delaware.

(Lamphere 2006; Brockmeyer 2015; Rogers and Nash 2003; Go Botany 2011-15)

Panicum amarum Ell. Bot. S. C. & Ga. 1: 121. 1816
Panicum amarum minus Vasey & Scribn.; Vasey, Bull. U. S. Dep. Agr. Bot. 8: 38. 1889. Panicum amaroides Scribn. & Merr.; Scribn. Circ. U. S. Dep. Agr. Agrost. 29: 5. 1901. Chasea amara Nieuwl. Am. Midi. Nat. 2: 64. 1911.
Plants glaucous and glabrous throughout; culms solitary from the nodes of extensively creeping, horizontal rootstocks, simple or occasionally branching from the lower nodes, 30-100 cm. high; leaf-sheaths overlapping but commonly narrow and partially exposing the short, very glaucous internodes; ligule dense and silky, about 3 mm. long; blades ascending or spreading, thick, 10-30 cm. long, 5-12 mm. wide, broadest at the base, flat below, involute toward the tip, the margins smooth; panicles short-exserted or included at base, one fourth to one third the height of the plant, or sometimes more, not more than 3 cm. wide, mostly few-flowered, the distant, appressed branches bearing scattered, short, appressed branchlets with approximate, short-pediceled spikelets; spikelets 5-6.5 mm. long, about 2. mm. wide and as much as 3 mm. thick, narrowly ovate, acuminate, strongly nerved; first glume clasping, two thirds to three fourths the length of the spikelet, acuminate, 7-9-nerved, the midnerve usually scabrous toward the apex; second glume slightly longer than the sterile lemma, both much exceeding the fruit, 9-nerved, the midnerves scabrous toward the apex; fruit 3.5 mm. long, about 1.5 mm. wide, narrowly ovate.
Type? locality: Probably South Carolina.
Distribution: Sandy seashore, Connecticut to Georgia; Mississippi.

Panicum amarulum Hitchc. & Chase, Contr. U. S. Nat. Herb. 15:
96. 1910.
Plants glaucous, but less so than in P. amarum, glabrous throughout, cespitose in large bunches sometimes as much as a meter across, 1-2 meters high; culms simple above the base, stout, sometimes 1 cm. thick; leaf-sheaths mostly overlapping; ligule dense, about 3 mm. long; blades erect or ascending, 20-50 cm. long, 5-12 mm. wide, broadest at the base, more or less involute, pilose at the base on the upper surface; panicles finally exserted, one third the height of the plant or more, 5-10 cm. wide, slightly nodding, compact, densely flowered, the long, fascicled branches erect but more or less spreading at their tips, spikelet-bearing from the base ; spikelets short-pediceled, 4.3-5.5 mm. long, 1.7-2 mm. wide, narrowly ovate, acuminate, strongly nerved; first glume half to two thirds as long as the spikelet, acuminate, 5-7-nerved; second glume slightly longer than the sterile lemma, both 7-9-nerved, pointed beyond the fruit; fruit 3-3.5 mm. long, about 1.4 mm. wide, narrowly ovate, bluntly pointed.
Type locality: Virginia Beach, Virginia.
Distribution: Sandy sea shores, Virginia to Florida; Bahamas; Cuba.

Perennials, Terrestrial, not aquatic, Rhizomes present, Rhizome elongate, creeping, stems distant, Stems nodes swollen or brittle, Stems erect or ascending, Stems solitary, Stems terete, round in cross section, or polygonal, Stems branching above base or distally at nodes, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems with inflorescence 1-2 m tall, Stems with inflorescence 2-6 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades 1-2 cm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades more or less hairy, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence a contracted panicle, narrowly paniculate, branches appressed or ascending, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets with 2 florets, Spikelet with 1 fertile floret and 1-2 sterile florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating below the glumes, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 4-7 nerved, Lemma similar in texture to glumes, Lemma 5-7 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins inrolled, tightly covering palea and caryopsis, Lemma straight, Palea present, well developed, Palea about equal to lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Panicum amarum is a species of grass known by the common name bitter panicum. It is native to North America, where it is found in coastal regions along the East Coast and Gulf Coast of the United States and into northeastern Mexico. It also occurs in The Bahamas and in Cuba.

This perennial grass grows from a thick rhizome. It has stems up to 2.5 meters tall and 1 centimeter thick. It may grow erect or bent over. The thick, firm leaves are up to half a meter long. They are bluish in color. The inflorescence is a narrowed panicle up to 80 centimeters long by 17 wide. Some seed is produced but most reproduction is vegetative, with new plants sprouting from tillers and the rhizome.

This grass is commonly used for dune stabilization projects. It is used to prevent erosion. The aboveground plant parts act as a windbreak, preventing the sand from being blown away, and the large root system stabilizes the sand in place. It can also be used in revegetation projects at other areas, such as mine spoils. Specifically, var. amarulum is valuable for these projects. The roots grow six feet deep. The cultivar 'Atlantic' is available.

A cultivar of P. amarum called 'Dewey Blue' is also used for ornamental purposes.