Panicum antidotale Retz. - Southern Arizona Data Services Program ...

USGS Weeds in the West project:
Status of Introduced Plants in Southern Arizona Parks
Factsheet for:
Panicum antidotale Retz.
William L. Halvorson, Principal Investigator
Patricia Guertin, Research Specialist
U.S. Geological Survey / Southwest Biological Science Center
Sonoran Desert Field Station
University of Arizona
125 Biological Sciences East
Tucson, Arizona 85721
Prepared by Patty Guertin
December 31, 2003
Funded by: U.S. Geological Survey
National Park Service

Table of Contents:
Panicum antidotale Retz......................................................................................................................3
blue panic grass, blue panic, blue panicum, giant panic grass, giant panic, perennial Sudan grass3
synonymous names of the species:................................................................................................... 3
species taxonomy ................................................................................................................................. 3
image of plant ...................................................................................................................................5
additional non-native species in the genus Panicum that occur in southern Arizona:.....................5
similar native or non-native species that could confuse identification.................................. 6
biology .................................................................................................................................................... 6
growth and reproductive strategy:...................................................................................................6
seed production:................................................................................................................................7
vegetative reproduction:...................................................................................................................7
seed dispersal:...................................................................................................................................7
seed longevity: ..................................................................................................................................7
ecology.................................................................................................................................................... 7
origin and history of introduction:...................................................................................................7
ecological distribution / habitat:.......................................................................................................8
climatic and site requirements, and limitations: ............................................................................8
germination:......................................................................................................................................9
soil preferences: ..............................................................................................................................10
competitive abilities:.......................................................................................................................10
why it does well as an exotic: .........................................................................................................11
effect on natural processes/description of the threat ............................................................... 11
known general distribution............................................................................................................. 11
United States: .....................................................................................................................................11
Arizona, by county:.............................................................................................................................12
National Park Service, southern Arizona group: ..............................................................................12
Casa Grande Ruins National Monument ......................................................................................12
Chiricahua National Monument....................................................................................................12
Coronado National Memorial.........................................................................................................13
Fort Bowie National Historic Site..................................................................................................13
Montezuma Castle National Monument and Montezuma Well unit ...........................................13
Organ Pipe Cactus National Monument .......................................................................................13
Saguaro National Park...................................................................................................................13
Tonto National Monument.............................................................................................................13
Tumacacori National Historical Park............................................................................................13
Tuzigoot National Monument ........................................................................................................13
Weeds in the West Project..................................................................................................................13
control methods and management strategies ............................................................................. 14
Grazing:...............................................................................................................................................14
Fire: .....................................................................................................................................................14
Control strategies: ..............................................................................................................................14
contacts or technical specialists .................................................................................................... 14
bibliography........................................................................................................................................ 16
additional sources and websites .................................................................................................... 20
websites with great plant photos: ......................................................................................................21
websites with simple plant descriptions and/or photos: ...................................................................21
2

Panicum antidotale Retz.
blue panic grass, blue panic, blue panicum, giant panic grass, giant
panic, perennial Sudan grass
family: Poaceae
synonymous names of the species:
� the first name in each species list is the current and synonymous name used by
Kartesz (1994).
� the name in bold type occurring within each species list indicates the plant name
used within these documents, which is also the name provided in the southern
Arizona NPS exotics database ‘soaraz~1.xls’ (Holden 1996).
Panicum antidotale Retz.
no synonymous names
species taxonomy
Panicum antidotale Retz., blue panic grass: From: California Department of Food and
Agriculture, EncycloWeedia (2002), FAO (2002), Felger (1990), Gould (1951), Hickman
(1993), Hitchcock (1951), Kearney and Peebles (1960), McDougall (1973), Ruyle and Young
(1997), Sankhla et al. (1975), USDA,NRCS, The PLANTS database (2001):
(A glossary is provided at the end of this section for the plant terminology used in this section.)
life strategy: a C4, perennial graminoid. Reproduces by seeds and from rhizomes.
2n=18, 36.
structure: an erect, many-branched, perennial graminoid, up to 10 ft. (2.5-3 m) tall,
with rhizomes. Sod-forming.
roots: fibrous roots growing to 18 in. (45 cm) deep, with thick knotty, bulbous rhizomes.
Rhizomes are robust, coarse, short, and bulbous; scales densely hairy.
stems: culms 2.7-6.7 ft. (8-20 dm) or more tall; culms branch from nodes.
branching: culms are usually branched from the nodes, creating an open stature/habit;
older plants often highly branched and bush-like.
culms/blades/sheath: culms 2.7-6.7 ft. (8-20 dm) or more tall; hard, wiry, more or less
woody as they mature, often glaucous; culm nodes swollen, often pubescent; culms
branch from swollen nodes. Blades are flat, 6-12 in. (15-30 cm) long, 0.2-0.5 in. (4-13 mm)
wide; upper surface glabrous; often glaucous. Sheaths open, glabrous; 1.6-3.2 in. (4-8 cm)
long.
collar/ligule/auricle: collar occasionally puberulent. Ligule membranous, densely
ciliate, 0.02-0.1 in. (0.5-2.5 mm) long. Auricles lacking.
inflorescence: inflorescence is a panicle. Panicle erect, with branches widely spreading
and flexuous, mostly open to contracted, ovate to elliptic, 5-12 in. (13-30 cm) long, dense
clusters of spikelets from branch base to tip; spikelets 1-2 per node.
3

spikelets/glumes/lemma/palea: spikelets 1-2 per node; pedicels less than 0.1 in. (2.5
mm) long. Spikelets consist of a lower sterile floret and an upper perfect, fertile floret;
spikelets detach as a unit; spikelets ovate to elliptic, 0.1 in. (2-3 mm) long, 1 mm wide;
strongly veined, more or less compressed dorsi-ventrally. Glumes and sterile lemma
membranous; first glume broad, acute to obtuse, clasps and is smaller than the second
glume, 0.06-0.1 in. (1.5-2.5 mm) long, about one-third to half the length of the spikelet, 5veined;
second glume and sterile lemma glabrous, blunt or abruptly short-beaked at
apex. Sterile and fertile florets about equal in length; sterile lemma 7-veined, tip acute,
palea about as long as lemma; fertile lemma about 2 mm long, hard, smooth, glossy,
margins flat, it tightly surrounds the palea.
taxonomic glossary (Harris and Harris 1997):
acute: tapering to a pointed apex, having more or less straight sides
ciliate: having a marginal fringe of hairs
decumbent: reclining along the ground, with tip ascending
dorsiventrally: flattened from top to bottom, so to have an upper and lower surface
flexuous: with curves and bends, sinuous
glabrous: smooth, hairless
glaucous: covered with a whitish to bluish waxy coating (bloom)
hispid: rough, having firm, stiff hairs
obtuse: blunt or rounded at the apex
ovate: egg-shaped outline, with attachment at broad end
papilla: a short, rounded nipple-like projection
papillose: having minute papillae
pedicel: the stalk of a solitary flower in an inflorescence, or of a grass spikelet
perfect: having both male and female reproductive organs
puberulent: having fine, short hairs
pubescent: covered with short, soft hairs
scabrous: rough to the touch (due to epidermal cell structure, or short stiff hairs)
4

image of plant
photo by Patty Guertin
photo by Patty Guertin
photo by Patty Guertin
photo by Patty Guertin
additional non-native species in the genus Panicum that occur in southern Arizona:
Panicum millaceum L., broomcorn millet, hog millet: From Gleason (1963), Gould
(1951), Hickman (1993), Hitchcock (1951), Kearney and Peebles (1960), McDougall (1973),
USDA,NRCS, The PLANTS database (2001): an annual graminoid, up to 40 in. (100 cm)
tall; a very variable plant; 2n=36. Roots fibrous. Culms stout, 8-40 in. (20-100 cm) tall, erect
or decumbent at base, pubescent at nodes, especially lower nodes. Leaf blades flat, as much
as 12 in. (30 cm) long, 0.2-0.8 in. (6-20 mm) or more wide, rounded at base, pubescent to
glabrous; leaf sheaths commonly densely papillose-hispid, 0.1-3.2 in. (3.5-8 cm) long; ligule
0.1 in. (1-3 mm) long, membranous, ciliate. Inflorescence a rather compact, dense panicle,
panicle pyramidal to cylindric, 3.2-12 in. (8-30 cm) long, sometimes nodding, often base is
included in leaf sheath, with erect, spreading branches, spikelets on short pedicels at ends of
5

anches; axis glabrous, branches very scabrous. Spikelets consist of 2 glumes, a lower
sterile floret and an upper fertile floret, more or less compressed dorsi-ventrally, 0.2 in. (4-5
mm) long, ovate, acuminate, pedicels 0.1 in. (1-3 mm) or more long; glumes unequal, first
glume half as long as spikelet or more, 5-veined; second glume and sterile lemma similar, 7-
11 veined, acute to acuminate; fertile lemma 0.1 in. (3-3.5 mm) long, smooth, shiny.
Caryopsis 0.1 in. (3-3.5 mm) long, smooth, shiny, yellowish- to reddish-brown.
United States: Arizona, California, Colorado, Connecticut, Delaware, Florida, Hawaii,
Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland,
Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada,
New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio,
Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Utah, Vermont,
Virginia, Washington, Wisconsin, Wyoming (USDA,NRCS, The PLANTS database 2001:
Map available at Website: http://plants.usda.gov/plants/ ; then enter the common or
scientific name).
Arizona, by county: in Cochise and Pima counties (Gould 1951, Kearney and Peebles 1960),
and Coconino County about 7100 ft. (McDougall 1973).
similar native or non-native species that could confuse identification
Generally, Panicum antidotale resembles Johnson grass (Sorghum halepense) with several
characteristics being similar, such as the size and coarseness of the plant, leaf size and a
prominent yellow midvein, a similar inflorescence, yet very different spikelets (Chambers
and Hawkins 2002, Guertin 2001, United States Department of Agriculture, Forest Service
1937). The spikelets of Panicum antidotale are smaller than those of Sorghum halepense;
typically measuring 0.1 in. (2-3 mm) long, versus Sorghum halepense's spikelets measuring
0.2-0.3 in. (4.5-7 mm) long.
biology
growth and reproductive strategy:
Panicum antidotale is a robust, short-lived perennial, warm-season, C4 graminoid
(Downton 1975, Ocumpaugh and Rodriguez 1998, Ragsdale and Welch 2000,
Sankhla et al. 1975) with a wide ecological amplitude (Pathak et al. 1983).
Panicum antidotale reproduces by seed and vegetative structures (rhizomes)
(California Department of Food and Agriculture, EncycloWeedia 2002). Most seed
germinates from late spring through mid-summer (California Department of Food
and Agriculture, EncycloWeedia 2002). During trials observing seed to seedling
development and its root-to-shoot ratio, Panicum antidotale displayed a fairly
constant ratio for its first 7 days of growth, averaged as 1.3:1 during this period of
growth (Simanton and Jordan 1986). Roundy et al. (1993) note that during trials root
to shoot ratios increased with decreased watering frequencies.
Growth from rhizomes begins in the late spring (Uvalde Research and Extension
Center 2000). Also, following a fire, rhizomes can initiate new shoots (California
Department of Food and Agriculture, EncycloWeedia 2002).
6

Panicum antidotale plant development is slow for the first 6-8 weeks (Barnard 1969
in FAO 2002). In trials in India, initial emergence of the inflorescence started about
35 days after growth response to the monsoon (Parihar et al. 1999). It flowers from
April to December (California Department of Food and Agriculture, EncycloWeedia
2002). Panicum antidotale stems become 'woody' at maturity (FAO 2002). Its seed
has a post-harvest dormancy (Myers 1940 in FAO 2002, Parihar et al. 1999).
Panicum antidotale's foliage is usually killed by freezing temperatures, but can
persist through winter with its vegetative rhizomes intact (California Department of
Food and Agriculture, EncycloWeedia 2002).
seed production:
no information found regarding number of seeds/plant.
vegetative reproduction:
Panicum antidotale can persist by its rhizomes (California Department of Food and
Agriculture, EncycloWeedia 2002) and can resprout after fires from its rhizomes
(California Department of Food and Agriculture, EncycloWeedia 2002).
seed dispersal:
Panicum antidotale is spread primarily by it seeds (Chambers and Hawkins 2002).
The seeds fall near the parent plant or can be dispersed at greater distances with
human activity, soil movement, water, animals, wind, or as seed or hay contaminants
(California Department of Food and Agriculture, EncycloWeedia 2002, GRIN 2000).
seed longevity:
Up to 2 years following Panicum antidotale seed maturation, maximum germination
can occur. At 5-8 years 80% germination can be reached, at 11 years 25%
germination can be reached, and at 13 years 3% germination can be reached (Myers
1940 in FAO 2002).
When kept under dry storage Panicum antidotale seed had germination percentages
of 82.33±6.24 and 83.33±4.26 at 1 and 2 years, respectively, 69.33±3l.2% at 3 years,
37.33±2.94% at 4 years, 19±2.74% at 6 years (Parihar and Rai 1985).
Barrow and Havstad (1995 in Simonin 2000) note that in a seeding trial in the
northern Chihuahuan Desert, Panicum antidotale seed survived cattle grazing with
little loss in germination.
ecology
origin and history of introduction:
Panicum antidotale is native to temperate and tropical Asia (in the Middle East to
India (Afghanistan, Iran, Yemen, India, and Pakistan)) (GRIN 2000). It was
introduced into the United States from India, via Australia (California Department
of Food and Agriculture, EncycloWeedia 2002, NewCROP 1999, Ruyle and Young
1997) in 1912 (NewCROP 1999, Tucson Plant Materials Center date unknown).
Several accessions and selections have been released, A-130 from Australia, P-15630
from Afghanistan, and a Seedling Drought Tolerant (SDT; selected from type A-130)
type (FAO 2002, Tucson Plant Materials Center date unknown, Wright and Dobrenz
1970 in Frasier et al. 1985). A-130 was tested and released in 1950 by the Tucson
Plant Materials Center (Tucson Plant Materials Center date unknown). Panicum
7

antidotale is presently used as a forage grass in pastures in Arizona, Texas, and
elsewhere (California Department of Food and Agriculture, EncycloWeedia 2002).
ecological distribution / habitat:
In its native area: Panicum antidotale grows on sand dunes and dry river beds in
northwest Pakistan, Afghanistan, and Iran (FAO 2002) tolerating temporary flooding
(FAO 2002). It also occurs in the natural grazing lands of northwestern India
(Narayanan and Dabadghao 1972 in Pathak et al. 1983).
On the North American continent: It is found across the southern United States;
sporadic in the southeastern U.S., and more common in the southwestern U.S. (based
on maps by Barkworth et al. 2003, USDA,NRCS, The PLANTS database 2001).
Panicum antidotale is found in the southern Mojave Desert and Sonoran Desert in
California up to 330 ft. (100 m) in elevation (California Department of Food and
Agriculture, EncycloWeedia 2002). In central and southern Arizona it is found at low
elevations on irrigated or flooded areas (Ruyle and Young 1997).
It is found on open, disturbed sites, roadsides, fields, irrigated pastures, irrigation
ditches and canal banks (California Department of Food and Agriculture,
EncycloWeedia 2002).
climatic and site requirements, and limitations:
Panicum antidotale is well suited as a warm-season pasture grass in Arizona
(Tucson Plant Materials Center date unknown). It is best adapted to areas having
summer rainfall, and having annual precipitation totals between 19.7-29.5 in. (50-75
cm) or lands that are irrigated (FAO 2002). In India, it grows in areas with less than
5.1 in. (13 cm) of rain (FAO 2002).
During greenhouse trials on several C4 Arizona range grasses, it was noted that
Panicum antidotale needs consistent water availability after germination for
seedling establishment; to enable elongation of its seminal roots ahead of the drying
front in the soil and to subsequently develop its adventitious roots (Roundy et al.
1993). To maintain soil water availability at the surface of the soil for the
development of these roots, frequent rainfall events are needed after germination.
During these trials, it took 11-15 days for initiation of adventitious roots to occur
(Roundy et al. 1993).
Panicum antidotale is not winterhardy in northern locations (NewCROP 1999) and
does not tolerate extended periods of freezing temperatures elsewhere (California
Department of Food and Agriculture, EncycloWeedia 2002). In Arizona, type A-130
will sustain injuries when temperatures lower below 10°F (-12°C) occur for prolonged
periods. Belyuchenko (1992) notes that Panicum antidotale's high mortality in
regions of colder climates and temperatures might be due to its regrowth buds
developing near the soil level being protected only by scales (versus some other
grasses having leaf rosettes, more litter covering regrowth buds, buds protected by
multiple leaf sheaths).
Panicum antidotale prefers full sunlit sites and does not tolerate shade well
(California Department of Food and Agriculture 2002, FAO 2002), although will
sometimes grow on partially shaded sites (FAO 2002).
Panicum antidotale does not tolerate flooded conditions well. Panicum antidotale
grows optimally with some summer moisture on fertile, well-drained soils (Anderson
1973, California Department of Food and Agriculture, EncycloWeedia 2002). It does
well when water is available or on floodplains where frequent flooding occurs
(Tucson Plant Materials Center date unknown). Established stands of Panicum
8

antidotale will persist, and sometimes thrive, under low precipitation or during
extended periods of drought, often remaining palatable (Tucson Plant Materials
Center date unknown, United States Department of Agriculture, Forest Service
1937).
Observations made after range plantings in various vegetation types in the Tonto
National Forest in Arizona demonstrated that after 30 years, Panicum antidotale
was still present as scattered and occasional plants in a chaparral vegetation type
(50 miles north of Phoenix). Elevation was approximately 3500 ft. (1067 m), with an
annual precipitation about 18 in. (45.7 cm) (Judd and Judd 1976).
Panicum antidotale responds markedly to nitrogen (FAO 2002).
germination:
Panicum antidotale has a post-harvest dormancy (Myers 1940 in FAO 2002). In
India, the seeds required an after-ripening lasting approximately 6 months (Parihar
et al. 1999). Several methods were used in trials to break seed dormancy; pre-chilling
was among the methods used (Parihar et al. 1999).
During greenhouse trials designed to identify the patterns of emergence and seedling
survival using different wetting-drying patterns, two types of Panicum antidotale
responded with differing emergence patterns. The SDT type had low initial
emergence percentages even after 3 days of wetting (1-3 days wet, 2-7 days dry) and
seemingly high seedling mortality, whereas the A-130 type had good initial
germination rates with minor seedling mortality during the dry period (Frasier et al.
1985).
Ranchers are advised to sow Panicum antidotale seed as soon as possible after night
temperatures reach 60°F (16°C) or higher, planting the seed 0.5 in. (1.3 cm) deep
(Tucson Plant Materials Center date unknown). Field studies showed that Panicum
antidotale seed emerged best from depths less than 0.47 in. (1.2 cm) (Winkel et al.
1991a in Roundy et al. 1993).
Panicum antidotale emergence is seemingly more successful on the more disturbed
sites, although available moisture also plays a part. During trials testing differing
seedbed preparations for range grasses (heavily trampled by cattle, lightly trampled,
land imprinting, root plowing or ripping, and undisturbed), Winkel and Roundy
(1991) report that during a wet year in southern Arizona in which rainfall was
consistent (having high frequency and intensity) between July 21 through August 25,
Panicum antidotale (type A-130) displayed very little emergence on undisturbed and
lightly trampled plots, moderate emergence on root-plowed plots, and its highest
emergence on ripped and heavily trampled plots. In a moderately wet year, the
pattern was roughly similar although emergence densities were considerably less.
During a dry year in which soil-surface water availability during emergence lasted 2-
3 days separated by 10 day dry periods, Panicum antidotale had little emergence for
any of the treatments.
Panicum antidotale (type A-130) emergence was tested using differing watering
regimes (daily waterings, watering on day 1 and day 5, or 1 day of watering) on
several microsites (having gravel, cracks in the soil crust, or litter, and a control
having bare, uncracked soil). When water was delivered each day, emergence was
highest in gravel and litter, and approximately half in the soil cracks. With
waterings day 1 and 5, emergence was highest when the seeds were sown in soil
cracks, with emergence in gravel and litter being lower and similar to each other, yet
seedlings located in the soil cracks began to die after 9 days. Emergence during the 1
day watering treatment was very low, with the highest number of seedlings
9

emerging on the gravel microsites (Winkel et al. 1991b). Panicum antidotale
germination tests in petri dishes demonstrated that this species needs 3-4 days of
wet conditions for germination to occur. A germination percentage of 70% was
observed with average minimum temperatures of 63°F (17°C) and average maximum
temperatures of 115° F (46°C) (Winkel et al. 1991b).
During germination trials in which seeds were exposed to a 24 hour schedule of 16
hours at 68°F (20°C) and 8 hours at 86°F (30°C) having light during the period of
high temperatures, Panicum antidotale germinated within a pH range of 4.0-11.5,
with highest percentages occurring between pH 8.0-11.5 and lowest percentages
within the range occurring near neutrality (Stubbendieck 1974).
In trials comparing increasing salt concentrations of specific ions (NaCl, MgCl2,
CaCl2, Na2SO4, MgSO4) against Panicum antidotale germination, Ryan et al. (1975b)
noted that Panicum antidotale germination percentage declined with increasing salt
concentrations, with a greater decline when the ions were sodium and magnesium
chloride, and when any cation was associated with chlorine.
Laboratory germination trials testing acid conditions on Panicum antidotale seed
showed that germination could occur under pH 3.0 (reduced by 75%), 4.0, 5.0, 7.0 but
not at 2.0 and below (Ryan et al. 1975a).
soil preferences:
Trew (1954 in FAO 2002) reports that Panicum antidotale grows best on fertile soils;
NewCROP (1999) notes that forage yields can be high on fertile, well-drained soils.
Panicum antidotale prefers heavy loams or dark clay soils (Trew 1954 in FAO 2002,
Ragsdale and Welch 2000) high in lime (Trew 1954 in FAO 2002). Trew (1954 in
FAO 2002) reports that it does not do well on sandy soils that are acid or low in
organic matter. Although, Tucson Plant Materials Center (date unknown) states that
Panicum antidotale is well adapted to deep alluvium soils (medium to fine textured)
when water is available or on floodplains where frequent flooding occurs.
Douglass King Company (date unknown) notes that for Panicum antidotale, soil
fertility is more important than the soil texture.
Panicum antidotale is tolerant of salinity (Ryan et al. 1975 in FAO 2002), but more
so to moderate amounts of alkali (Ruyle and Young 1997, Ryan et al. 1975 in FAO
2002) caused by sodium and magnesium rather than chlorides (Ryan et al. 1975 in
FAO 2002). It is also can tolerate moderate levels of soil sodicity, with yield reducing
by 50% at an approximate ESP (Exchangeable Sodium Percentage) of 55 (Kumar and
Abrol 1982).
competitive abilities:
California Department of Food and Agriculture, EncycloWeedia (2002) reports that
Panicum antidotale can compete with Johnsongrass.
On-site interspecific and intraspecific competition were demonstrated in a 3 year
trial in India testing spacing and weeding patterns that would potentially favor
increased yields of Panicum antidotale. It was found that when Panicum antidotale
plants were spaced 35 in. (90 cm; versus 12 in. (30) cm, and 24 in. (60 cm)) apart,
plant height and basal diameter increased (Chakravarty and Verma 1972). When
Panicum antidotale plants had competing weeds removed from its immediate area
(versus a control, with competing weeds not removed), plant height increased
significantly in its second year of growth with both 1 and 2 weedings, and number of
tillers, and basal diameter increased significantly after two weedings during its
second year of growth (Chakravarty and Verma 1972). Plant growth was more
10

influenced by weeding treatments than by plant spacing. With only one weeding to
reduce competition during a year having very good precipitation (21 in. (53.3 cm)),
Panicum antidotale had a 284% increase in forage yield (Chakravarty and Verma
1972).
why it does well as an exotic:
Panicum antidotale has a very deep root system (FAO 2002) potentially reaching
deeper soil water. Panicum antidotale also has a high degree of drought tolerance in
the limited moisture conditions of the desert grasslands (FAO 2002, Wright 1966 in
Ryan et al. 1975), and responds quickly to summer storms (FAO 2002).
After a fire, Panicum antidotale rhizomes can develop new shoots (California
Department of Food and Agriculture, EncycloWeedia 2002).
effect on natural processes/description of the threat
Marshall et al. (2000) reports that Panicum antidotale competes with and displaces native
plant species.
known general distribution
United States:
Alabama, Arizona, California, Hawaii, New Mexico, North Carolina, South Carolina,
Texas, Utah (USDA,NRCS, The PLANTS database 2001: Map available at Website:
http://plants.usda.gov/plants/ ; then enter the common or scientific name).
11

Arizona, by county:
in Cochise County (Gould 1951, Kearney and Peebles 1960), Pima County (Felger
1990, Gould 1951), and Yavapai County (McDougall 1973). Ruyle and Young (1997)
report that it also occurs in central Arizona at low to moderate elevations, but
locations aren’t reported.
To view recently developed (and developing) maps of distribution on this continent, check
Website: http://www.herbarium.usu.edu/webmanual/default.htm and make selections for
the map of the desired species; the 'Manual of Grasses for North America' Project,
Barkworth et al. (2003).
National Park Service, southern Arizona group:
Casa Grande Ruins National Monument
source listing species’ presence in park:
no sources found
Chiricahua National Monument
source listing species’ presence in park:
no sources found
12

Coronado National Memorial
source listing species’ presence in park:
no sources found
Fort Bowie National Historic Site
source listing species’ presence in park:
no sources found
Montezuma Castle National Monument and Montezuma Well unit
source listing species’ presence in park:
no sources found
Organ Pipe Cactus National Monument
source listing species’ presence in park:
Felger, R.S. 1990. Non-native plants of Organ Pipe Cactus National Monument,
Arizona. Technical Report No. 31. U.S. Geological Survey, Cooperative Park Studies
Unit, The University of Arizona and National Park Service, Organ Pipe Cactus
National Monument. 93 pp.
Felger, R.S. and S. Rutman. 2000; draft. The flora of Organ Pipe Cactus National
Monument. 18 pp.
Saguaro National Park
source listing species’ presence in park:
no sources found
Tonto National Monument
source listing species’ presence in park:
no sources found
Tumacacori National Historical Park
source listing species’ presence in park:
no sources found
Tuzigoot National Monument
source listing species’ presence in park:
no sources found
Weeds in the West Project
While completing distribution mapping between Spring 1999 through Spring 2001 for the
USGS Weeds in the West project in the southern Arizona National Park Service
management units, Panicum antidotale Retz. (blue panic grass) was found in the following
parks (Guertin 2001):
� Organ Pipe Cactus National Monument
13

control methods and management strategies
There is virtually no information available on control and management of Panicum
antidotale; its past and present use as a rangeland species for forage production
precludes the need for its elimination. California Department of Food and
Agriculture, EncycloWeedia (2002) and Chambers and Hawkins (2002) state that
Panicum antidotale can be controlled using the same control techniques as those
used for Sorghum halepense (Johnson grass).
Grazing:
Fire:
Panicum antidotale is a palatable forage plant often provided to cattle (Tucson Plant
Materials Center date unknown, Ruyle and Young 1997), and sheep, although only
as hay to horses (Tucson Plant Materials Center date unknown). It can cause
prussic acid poisoning during certain stages of its growth (Ragsdale and Welch 2000).
Although, FAO (2002) notes that Panicum antidotale cannot withstand heavy, close
grazing.
The following summary is provided so as to understand anticipated and favorable
responses from the plant, with the potential that this information be used to develop
a strategy of control and/or management: To obtain heaviest yields in Rajasthan,
India, Panicum antidotale should be cut at 20-day intervals to 4 in. (10 cm) in a wet
year, and at 30-day intervals to 6 in. (15 cm) high during a normal year (Dabadghao
et al. 1973 in FAO 2002). It needs heavy intermittent grazing to keep it at a
nutritious stage of growth and requires 9.8-11.8 in. (25-30 cm) of remaining stubble
after cutting or grazing (FAO 2002). After an area is grazed it is recommended to
remove stems by mowing or slashing to encourage new growth from the base of the
plant (FAO 2002).
Panicum antidotale is resistant to fire (FAO 2002) potentially resprouting after fire
occurs.
Control strategies:
California Department of Food and Agriculture, EncycloWeedia (2002) notes that
although there is no documented evidence, the same control methods that are used
against Sorghum halepense (Johnsongrass) may also work against Panicum
antidotale. (see plant factsheet for Sorghum halepense (Johnsongrass)).
contacts or technical specialists
Dr. Francis E. Northam (Ed Northam)
Noxious Weed Coordinator, Plant Services Division
Arizona Department of Agriculture
1688 West Adams Street
Phoenix, Arizona 85007
Phone: (602) 542-3309: FAX: (602) 542-1004 e-mail: ed.northam@agric.state.az.us
Ed works state-wide primarily with noxious agricultural weeds, yet has also done some
work to get non-native invasive plants listed that impact Arizona’s natural
environments
He indicated he would provide, as requested, information regarding:
14

� weed biology
� control/management of weeds
Dr. John H. Brock
Professor of Applied Biological Science
Coordinator of Sustainable Technologies, Agribusiness and Resources (STAR) Research
Center
Arizona State University East
7001 E. Williams Field Rd.
Mesa, Arizona 85212
Phone: (480) 727-1240; FAX (480) 727-1961 e-mail: john.brock@asu.edu
Dr. Brock has done:
� invasive plant work (including control treatments) in essentially all the major
vegetation types in Arizona, except the highest elevation types like mixed
conifer.
April Fletcher, Arizona Interagency Weed Action Group
U.S. Fish and Wildlife Service
P. O. Box 1306
500 Gold Ave.
Albuquerque, New Mexico 87103
e-mail: April_Fletcher@fws.gov
April works region-wide with on-the-ground folks. Arizona Interagency Weed Action
Group (IWAG) is an ad-hoc group; working on specific projects identified as species of
concern by the group. IWAG consists of invasive weed folks from state and Federal
resource management agencies.
April is:
� acquainted with control methods for numerous species
� she knows many professionals who are doing control work, so, when she can’t
supply an answer, she can usually provide contacts who can.
Jim Horsley, Southwest Vegetation Management Association
Arizona Department of Transportation
2104 S. 22nd Avenue
Phoenix, Arizona 85009
Phone: (602) 712-6135 email: jhorsley@dot.state.az.us
Jim indicated at ADOT they manage and control a number of native and non-native
invasive species. Their experience includes
� Centaurea solstitialis (Yellow) and Centaurea melitensis (Malta) star thistle,
Onopordum acanthium (Scotch), Carduus nutans (Musk), and Cirsium vulgare
(Bull) thistle, Acroptilon repens (Russian), Centaurea biebersteinii / Centaurea
maculosa (spotted), and Centaurea diffusa (diffuse) knapweed, Alhagi maurorum
(Camelthorn), Halogeton glomeratus (Halogeton), Salsola sp. (Russian thistle,
tumbleweed), Linaria damatica (Dalmation toadflax), Cardaria draba (Hoary
cress), Tribulus terrestris (Puncture vine), Cenchrus sp. (sandbur), Convolvulus
arvensis (Field bindweed), Sorghum halepense (Johnsongrass), Pennisetum
ciliare (Buffelgrass), Pennisetum setaceum (Fountain grass), several mustards,
Verbascum sp. (mullein), Heterotheca subaxillaris (Camphorweed) and several
others.
Jim has
� personal experience statewide
� and, has access to other experts from several states in the southwest.
15

ibliography
Anderson, E.R. 1973. Effects of flooding on some tropical grasses. Journal of the Australian
Institute of Agricultural Science 40:53.
Barkworth, M.E., K.M. Capels, and L.A. Vorobik (eds.). 2003. Manual of grasses for North
America Project. Utah State University.
for plant distribution maps, see: Website:
http://herbarium.usu.edu/webmanual/default.htm then select desired species,
and menu selection (map, illustration, treatment, synonymy, notes)
Barnard 1969. reference missing in FAO (2002).
Barrow, J.R., and K.M. Havstad. 1995. Natural methods of establishing native plants on
arid rangelands. In: Roundy, B.A., E.D. McArthur, J.S. Halley, and D.K. Mann
(compilers). Proceedings: Wildland shrub and arid land restoration symposium;
October 19-21, 1993, Las Vegas, Nevada. U.S. Department of Agriculture, Forest
Service, Intermountain Research Station, General Technical Report INT-GTR-
315, Ogden, Utah. p. 44-45.
Belyuchenko, I.S. 1992. Resistance of perennial grasses of various origin to low
temperatures. Soviet Agricultural Sciences 7:13-18.
California Department of Food and Agriculture, EncycloWeedia. 2002. Panicum. Ed by:
Healy, E.A., S. Enloe, J.M. DiTomaso, B. Roberson, N. Dechoretz, S. Schoenig, P.
Akers, L. Butler, and J. Garvin. Non-Cropland Weed group, UC Extension
Service, Weed Science Program, Department of Vegetable Crops, The University
of California. Davis, CA. 95616. website:
http://pi.cdfa.ca.gov/weedinfo/PANICUM2.htm
Callihan, B., L. Smith, J. McCaffrey, and E. Michalson. 1995. Yellow starthistle
management for small acreages. University of Idaho, Cooperative Extension
System, Agricultural Experiment Station; CIS 1025. 8 pp.
Chakravarty, A.K., and C.M. Verma. 1972. Study on the pasture establishment technique
VI. Effect of different spacings and weedings on establishment and forage
production of Cenchrus ciliaris Linn., Lasiurus sindicus Henr. and Panicum
antidotale Retz under arid conditions. Annals of Arid Zone 11(1-2):60-66.
Chambers, N., and T.O. Hawkins. 2002. Invasive plants of the Sonoran Desert, a field
guide. Sonoran Institute, Environmental Education Exchange, National Fish
and Wildlife Foundation, with funding from many other organizations. Tucson,
Arizona. 120 pp. in English and Spanish.
Dabadghao, P.M., R.D. Roy, and S.P. Marwaha. 1973. The effect of interval and intensity of
defoliation on the dry matter production of some important grass species of
western Rajasthan. Annals of Arid. Zone 12:1-8.
Douglass King Company. date unknown. Panicgrass, blue (Panicum antidotale). Douglass
King Company Grass Book, Grass Seed. Website:
http://www.dkseeds.com/gbpanbl.html
16

Downton, W.J. 1975. The occurrence of C4 photosynthesis among plants. Photosynthetica
9(1):96-105.
ExToxNet. 2002. USDA/Extension Service/National Agricultural Pesticide Impact
Assessment Program, A Pesticide Information Project of Cooperative Extension
Offices of Cornell University, Oregon State University, the University of Idaho,
and the University of California at Davis and the Institute for Environmental
Toxicology, Michigan State University. Website:
http://ace.orst.edu/info/extoxnet/ghindex.html
FAO. 2002. Panicum antidotale Retz. Grassland Index. Website:
http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGP/AGPC/doc/GBASE/Da
ta/pf000275.HTM
Felger, R.S. 1990. Non-native plants of Organ Pipe Cactus National Monument, Arizona.
Technical Report No. 31. U.S. Geological Survey, Cooperative Park Studies Unit,
The University of Arizona and National Park Service, Organ Pipe Cactus
National Monument. 93 pp.
Frasier, G.W., J.R. Cox, and D.A. Woolhiser. 1985. Emergence and survival response of
seven grasses for six wet-dry sequences. Journal of Range Management
38(4):372-377.
Gleason, H.A. 1963. The new Britton and Brown illustrated flora of the northeastern
United States and adjacent Canada; Vol. 1. The New York Botanical Garden.
Hafner Publishing Co., Inc., New York. 482 pp.
Gould, F.W. 1951. Grasses of the southwestern United States. The University of Arizona
Press. Tucson, AZ. 352 pp.
GRIN. 2000. Grin Taxonomy. United States Department of Agriculture, Agricultural
Research Service, The Germplasm Resources Information Network (GRIN).
Website: http://www.ars-grin.gov/npgs/tax/index.html then click on 'simple
queries of species data' and search for plant species.
Guertin, P. 2001. Observations made during the duration of weed distribution mapping for
the USGS Weeds in the West project occurring in the southern Arizona National
Park Service management areas. May 1999-June 2001. USGS/BRD, Sonoran
Desert Field Station, The University of Arizona, 125 Biological Sciences East,
Tucson, Arizona, 85721.
Harris, J.G., and M.W. Harris. 1997. Plant identification terminology: an illustrated
glossary. Spring Lake Publishing, Spring Lake, Utah. 197 pp.
Hickman, J.C. (ed.). 1993. The Jepson manual: higher plants of California. University of
California Press. Berkeley and Los Angeles, CA. 1400 pp.
Hitchcock, A.S.; revised by Chase, A. 1951. Manual of the grasses of the United States.
United States Department of Agriculture, Misc. Publ. No. 200. Division of Plant
Exploration and Introduction, Bureau of Plant Industry, Soils, And Agricultural
Engineering. Agricultural Research Administration. Government Printing Office,
Washington, D.C. 1051 pp.
17

Holden, M. 1996; unpublished. Exotic plant species list, compiled for southern Arizona
parks from park floras and exotic plants lists. National Park Service; Saguaro
National Park; Tucson Mountain District; 'soazex~1.xls' database, in MS Excel.
Horowitz, M. 1996. Bermudagrass (Cynodon dactylon): A history of the weed and its control
in Israel. Phytoparasitica 24(4):305-320.
Judd, B.I., and L.W. Judd. 1976. Plant survival in the arid southwest 30 years after
seeding. Journal of Range Management 29(3):248-251.
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States,
Canada, and Greenland: Volume I - Checklist. The biota of North America
Program of the North Carolina Botanical Garden. Timber Press, Portland,
Oregon. 622 pp.
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States,
Canada, and Greenland: Volume II - Thesaurus. The biota of North America
Program of the North Carolina Botanical Garden. Timber Press, Portland,
Oregon. 816 pp.
Kearney, T.H. and R.H. Peebles. 1960. Arizona flora. University of California Press,
Berkeley and Los Angeles, California. 1085 pp.
Kumar, A., and I.P. Abrol. 1982. Relative tolerance of grasses to sodic soils. Indian
Farming 32:41-43.
Marshall, R.M., S. Anderson, M. Batcher, P. Comer, S. Cornelius, R. Cox, A. Gondor, D. Gori,
J. Humke, R. Paredes Aquilar, I.E. Parra, and S. Schwartz. 2000. An ecological
analysis of conservation priorities in the Sonoran Desert Ecoregion. Prepared by
The Nature Conservancy Arizona Chapter, Sonoran Institute, and Instituto del
Medio Ambiente y el Desarrollo Sustentable del Estado de Sonora with support
from the Department of Defense Legacy Program, Agency and Institutional
partners. 146 pp.
McDougall, W.B. 1973. Seed plants of northern Arizona. The Museum of Northern Arizona.
Flagstaff. 594 pp.
Myers, A. 1940. Longevity of seeds of native grasses. Agricultural Gazette NSW 51:405.
Narayanan, T.R., and P.M. Dabadghao. 1972. Forage crops of India. I.C.A.R., New Delhi,
India.
NewCROP. 1999. Introduced panicgrasses. Purdue University, Center for New Crops and
Plants Products. Website:
http://www.hort.purdue.edu/newcrop/Crops/Introduced_Panicgrasses.html
Ocumpaugh, W.R., and O. Rodriguez. 1998. Pasture forage production: integration of
improved pasture species into south Texas livestock production systems. Texas
A&M University Agricultural Research Station, Beesville, Texas, and G.E. Pogue
Seed Co. Inc., Kenedy, Texas. Website:
http://cnrit.tamu.edu/cgrm/whatzhot/Laredo/ocumpaugh.html
18

Oregon State University, Weed Science Program. 1998. Table 1. Herbicide classification
according to primary site of action. Oregon State University, Extension,
Research, and the Department of Crop and Soil Science. Website:
http://www.css.orst.edu/weeds/Publications/table1.html
Parihar, S.S., P. Agarwal, and V. Shankar. 1999. Seed production and seed germination in
blue panic grass (Panicum antidotale Retz.). Tropical Ecology 40(1):75-78.
Parihar, S.S., and P. Rai. 1985. Longevity and seed germination in range grasses. Indian
Journal of Ecology 12(1):168-170.
Parker, R. 1997. Control of problem weeds. In: William R,D., D. Ball, T.L. Miller, R.
Parker, J.P. Yenish, R.H. Callihan, C. Eberlein, G.A. Lee, and D.W. Morishita,
compilers. Pacific Northwest 1997 Weed Control Handbook. Oregon State
University, Corvallis, Oregon. p. 304 - 342.
Pathak, P.S., P. Rai, and R. Debroy. 1983. Comparative growth analysis of Panicum
antidotale Retz. cultivars. Indian Journal of Ecology 10(1):141-143.
Ragsdale, B.J., and T.G. Welch. 2000. Descriptions of range and pasture plants. Texas
A&M University System, Texas Cooperative Extension Service, Publication E-32.
Website: http://agpublications.tamu.edu/pubs/rem/e32.pdf
Rice, Jr., R.P. 1992. Nursery and landscape weed control manual. Thompson Publications,
Fresno, California. 290 pp.
Ross, M.A. and C.A. Lembi. 1985. Applied Weed Science. Macmillan Publishing Company,
New York. 340 pp.
Roundy, B.A., V.K. Winkel, J.R. Cox, A.K. Dobrenz, and H. Tewolde. 1993. Sowing depth
and soil water effects on seedling emergence and root morphology of three warmseason
grasses. Agronomy Journal 85(5):975-982.
Ruyle, G.B. and D.J. Young, (eds.). 1997. Arizona range grasses. Cooperative Extension,
publication AZ97105, College of Agriculture, The University of Arizona, Tucson,
Arizona. Website: http://ag.arizona.edu/pubs/natresources/az97105/
Ryan, J., S. Miyamoto, and J.L. Stroehlein. 1975a. Effect of acidity on germination of some
grasses and alfalfa. Journal of Range Management 28(2):154-155.
Ryan, J., S. Miyamoto, and J.L. Stroehlein. 1975b. Salt and specific ion effects on
germination of four grasses. Journal of Range Management 28(1):61-64.
Sankhla, N., H. Ziegler, O.P. Vyas, W. Stichler, and P. Trimborn. 1975. Eco-physiological
studies on Indian arid zone plants. 5. A screening of some species for the C4pathway
of photosynthetic CO2-fixation. Oecologia 21(2):123-129.
Simanton, J.R., and G.L. Jordan. 1986. Early root and shoot elongation of selected warmseason
perennial grasses. Journal of Range Management 39(1):63-67.
Simonin, K.A. 2000. Bouteloua eriopoda. In: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Research Station, Fire Sciences Laboratory. 2002. Fire
19

Effects Information System. Website:
http://www.fs.fed.us/database/feis/plants/graminoid/boueri/all.html
Stubbendieck, J. 1974. Effect of pH on germination of three grass species. Journal of Range
Management 27(1):78-79.
Trew, E.M. 1954. Blue panic grass. Texas Agricultural Experiment Station Bulletin B-245.
Tucson Plant Materials Center. date unknown. Management and uses of blue panicum.
Panicum antidotale. USDA-NRCS Tucson Plant Materials Center, Tucson,
Arizona. Website: http://www.plantmaterials.nrcs.usda.gov/pubs/azpmcrnpaan4a130.pdf
Uvalde Research and Extension Center. 2000. Blue panicum (Panicum antidotale Retz.).
Texas A&M University System, Research and Extension Center Virtual
Herbarium. Website: http://uvalde.tamu.edu/herbarium/paan.htm
United States Department of Agriculture, Forest Service. 1937. Range Plant Handbook.
United States Government Printing Office, Washington, D.C. 539 pp.
United States Department of Agriculture, Natural Resources Conservation Service. 2001.
The PLANTS database, Version 3.1 (http://plants.usda.gov/plants/). National
Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Winkel, V.K., and B.A. Roundy. 1991. Effects of cattle trampling and mechanical seedbed
preparation on grass seedling emergence. Journal of Range Management
44(2):176-180.
Winkel, V.K., B.A. Roundy, and D.K. Blough. 1991a. Effects of seedbed preparation and
cattle trampling on burial of grass seeds. Journal of Range Management
44(2):171-175.
Winkel, V.K., B.A. Roundy, and J.R. Cox. 1991b. Influence of seedbed microsite
characteristics on grass seedling emergence. Journal of Range Management
44(3):210-214.
Wright, L.N. 1966. Blue panicgrass for Arizona and the southwest. Arizona Agricultural
Research Station Technical Bulletin 173. 27 pp.
Wright, L.N., and A.K. Dobrenz. 1970. Water use in relation to management of blue
panicgrass (Panicum antidotale Retz.). Journal of Range Management 23:193-
196.
additional sources and websites
Cooperative State Research, Education, and Extension Service
Website: http://www.reeusda.gov/1700/statepartners/usa.htm
This website brings you to an interface to connect with Cooperative Extension programs
throughout the United States; select the desired state, enter a link, often there is a search
option in which information on a plant can be searched for.
20

USDA, Forest Service, Rocky Mountain Research Station, September 2002 has published
'Linking Wilderness Research and Management. Volume 4 - Understanding and Managing
Invasive Plants in Wilderness and Other Natural Areas. An Annotated Reading List.
General Technical Report RMRS-GTR-79-volume 4 This volume is available on the Web;
Website: http://www.fs.fed.us/rm/pubs/rmrs_gtr079_4.pdf (Website:
http://www.fs.fed.us/rm/pubs/rmrs_gtr079_4.html provides some information if problems
occur in viewing this file)
websites with great plant photos:
http://www.csdl.tamu.edu/FLORA/image/k4634900.htm
http://ces.asu.edu/collections/vasc_image_library/ImageIndex.jsp then click on
appropriate letter, and then scroll down and click on appropriate name
websites with simple plant descriptions and/or photos:
http://uvalde.tamu.edu/herbarium/paan.htm
21