Plant Guide For Purple Needlegrass

Plant GuidePURPLE NEEDLEGRASSNassella pulchra (Hitchc.)BarkworthPlant Symbol NAPU4Contributed by: USDA NRCS California State Office andLockeford Plant Materials Center, CaliforniaWildlife/livestockPurple needlegrass is a valuable forage species whichprovides food for deer, elk and other wildlife. It can be animportant source of food for livestock, having moderateprotein values and high palatability (USDA 2009). Theleaves green up early in the season and provide goodquality early forage for grazing animals. Unfortunately,but the sharp-tipped seeds and awns can become injuriousas they dry later in the season. However, shatter iscomplete within a month of maturity and difficulties canbe avoided through pasture management. This species isgenerally not that important as a livestock forage as itfails to make up a significant portion of the forage baseover most of its range, and because under rangelandconditions livestock tend to avoid it later in the season.The fact that livestock do not prefer the species overothers is part of reason why it persists in such abundancewhen compared to other natives of greater palatability forlivestock.Low water use lawn and landscapingPurple needlegrass is an excellent native grass for use inlow water landscaping. The species has also been used innative grass lawns, but its bunching habit prevents it fromforming a uniform sod. Animals such as dogs have beenknown to get the seed lodged in their fur. The awns thenbreak off leaving the small, sharp seed which can burrowunder the skin. These problems can be avoided bymowing the seed prior to maturity. Lawns should bemowed to no lower than 4 inches (10 cm).Purple needlegrass. Photo by Lynn Watson.Alternate NamesPurple stipa, purple tussockgrassUsesRestorationPurple needlegrass, the state grass of California, isappropriate for restoration and range improvementthroughout much of California’s Central Valley andfoothills. The species is highly valued as an erosioncontrol grass due to its longevity, tolerance to poor soilconditions and its ability to establish a coarse root systemon disturbed sites with low soil fertility. The species isknown for establishing easily on disturbed soils, roadsidesand gopher mounds. It has been successfully used in reestablishing native perennial grasses following weedcontrol on sites previously occupied by introduced annualspecies.StatusConsult the PLANTS Web site and your State Departmentof Natural Resources for this plant’s current status (e.g.threatened or endangered species, state noxious status,and wetland indicator values).DescriptionGeneral: Grass Family (Poaceae). Purple needlegrass is adensely tufted, long-lived, upright perennial bunchgrasswith conspicuously long awns. It has numerous basalleaves and a distinct nodding habit at anthesis. Plants aregenerally 2 to 3 feet tall (0.6 to 0.9 m) producing an open,nodding panicle of 4 to 8 inches (10 to 20 cm). The leafblades are smooth to finely hairy. Basal blades are long,flat and 0.03 to 0.2 inches (0.8 to 3.5 mm) wide. Theseeds (florets) range from 0.3 to 0.4 inches (7.5 to 11.5mm) long with a hairy lemma and a twice-bent awnreaching 1.5 to 4 inches (38 to 100 mm) in length(Hickman 1993). There are typically between 115,000and 150,000 seeds/lb in a well processed seed lot.Unprocessed seed with the awns still attached can have asfew as 50,000 seeds/lb.

Purple needlegrass has been reported to root as deep as 16feet (4.8 m) in deep soils (Netstate 2009), but the rootsmore typically range from 2 to 6 feet deep (pers. obs.).Plants become dormant after seed production, but begingrowth again with fall rain. Plants will also regreen aftersummer dormancy even without the presence ofprecipitation. This is believed to be in response toshortening day lengths.Purple needlegrass is wind pollinated. Plants canregenerate either asexually by tillering and bunchfragmentation, or via seed dispersal. Seed burial isfacilitated by the sharp pointed seed and long awns whichtwist as they dry, driving the seed into the soil.Purple needlegrass has been shown to have very high selfpollinating rates (Larsen et al. 2001). Results indicate thatinbreeding and/or selection have contributed to thesignificant differentiation of needlegrass populations.There are two native and one introduced Nassella specieswhich are commonly mistaken for purple needlegrass inCalifornia. The native needlegrasses, nodding needlegrass(N. cernua) and foothill needlegrass (N. lepida), have awavy distal awn segment which differs from the straightdistal awn segment found on purple needlegrass(Hickman 1993). Additionally, nodding needlegrasstypically has a longer awn and thinner seed than purpleneedlegrass, while foothill needlegrass has much smallerseed and shorter awns than purple needlegrass.Seed of Nassella manicata (left) and N. pulchra (right). Photoby James Effenberger, California Department of Food andAgriculture, 2009.DistributionNassella manicata is native to South America and hasbeen detected in California in the San Francisco Bay areaand near Folsom, California (Amme 2003). It waspreviously misidentified as N. formaricum in The JepsonManual (Barkworth 2007). The Flora of North Americaseparates the two species with N. manicata having florets6-8 mm long with lemmas glabrous between the veins atmaturity, and N. pulchra having florets 7.5 –11.5 mmlong with lemmas evenly pubescent at maturity(Barkworth 2007).County level distribution map of purple needlegrass. Image fromPLANTS database (2009).The distribution of purple needlegrass prior to Europeansettlement is undetermined. It was previously widelybelieved that purple needlegrass was a climax species inCalifornia, occupying much of the valley and coastalgrasslands. New studies suggest, however, that beardlesswildrye may have been more dominant on heavier clays,while purple needlegrass was the dominant grass in moresandy areas (Holstein 2001). Purple needlegrass currentlyoccurs on the west side of the Coast Range from northernBaja California north to southern Oregon, the CentralValley and foothills of the Cascade Range and Sierra

Nevada as well as the Channel Islands. For currentdistribution consult the Plant Profile page for this specieson the PLANTS Web site.HabitatPrior to European settlement, purple needlegrass was oneof the dominant grass species of California’s valleygrasslands and foothills. The species now occurs ingrasslands, oak and pine woodlands, mixed evergreenforests, chaparral, and coastal scrub, but has beenreplaced in many instances by introduced annual grassessuch as annual rye (Lolium perenne ssp. multiflorum),wild oat (Avena fatua), slender oat (A. barbata), ripgutbrome (Bromus diandrus), soft chess (B. hordeaceus),mouse barley (Hordeum murinum), and rattail fescue(Vulpia myuros).In natural plant communities it is frequently associatedwith Idaho fescue (Festuca idahoensis), prairie junegrass(Koeleria macrantha), Sandberg bluegrass (Poa secunda)and bottlebrush squirreltail (Elymus elymoides) (Heady1977). It can also be found with California oatgrass(Danthonia californica), California fescue (Festucacalifornica), tussockgrass (Nassella lepida), beardlesswildrye (Leymus triticoides), and melic grass (Melicaspp.). In coastal areas purple needlegrass is found inassociation with red fescue (Festuca rubra) andCalifornia brome (Bromus carinatus).AdaptationPurple needlegrass grows in oak woodland, chaparral andgrasslands in areas receiving between 8 and 40 inches (20to 100 cm) of annual precipitation. Its elevational rangeextends from sea level to 4,300 feet (1300 m). It is welladapted to droughty soils, clays and serpentine soils. Thespecies grows well in full sun as well as partial shade andis tolerant of extreme summer heat and drought. Purpleneedlegrass does not tolerate being overshaded by nonnative annuals. Some ecotypes of the species have partialflood tolerance.EstablishmentFor best results, seed should be planted to a depth of ¼ to½ inch into a firm weed-free seedbed. The pure standrecommended drill seeding rate is 9.5 lb pure live seed(PLS) per acre for approximately 25 seeds/ft². This isbased on 115,000 PLS/lb. For broadcast applications thepure seed rate is 15 lbs/ac. Planting 1 lb/acre yieldsapproximately 3 seeds/ft². Seed can be planted in earlyspring, but late dormant fall seeding is recommended forbest emergence and competition against annual weeds.For seed mixtures, using rice hulls or another dilutent isrecommended to prevent the settling of smaller seed inthe mixture. Like other native perennial grasses, this platnshould generally not be seeded in mixes including annualgrasses which reduce the likelihood of establishment.During establishment, disturbance should be minimized.Purple needlegrass does not compete well with annualgrass or broadleaf weeds during the establishment periodbecause of slow establishment during the first year. Itrequires bare ground to re-seed, but volunteers readilyinto openings and increases once it is established. Standsare usually maintained by abundant seed production innon-grazed or properly grazed areas. The species can alsoexpand vegetatively when tussocks are fragmented.ManagementThe most important management issue for purpleneedlegrass seedings is preventing overwhelming weedcompetition, especially from exotic grasses but alsoaggressive broadleaf weeds. Studies have shown thepresence of annual exotic grasses can reduce the growthand seed production of purple needlegrass at alldevelopmental stages (Hamilton et al. 1999). Youngneedlegrass seedlings grow at a much slower rate thanmost weeds. The weeds easily overshade and outcompetenew seedlings for sunlight and can dramatically impactestablishment. Where possible, control competingvegetation. Some options for competition control includemowing, herbicide applications and closely controlled andtimed grazing. It is a good idea to control weeds prior toneedlegrass emergence if possible. Other options includemowing, herbicide wicking and limited grazing.New seedings should not be grazed for two to three yearsfollowing planting to ensure full establishment. However,under heavy competition by weeds, limited grazing canopen the plant canopy and allow sunlight for newseedlings. Purple needlegrass should not be grazed duringflowering to ensure formation of the seed and to allowfood storage in the crown. The plants have a goodtolerance for mowing, especially after seed maturity, butcan be mowed earlier.Purple needlegrass is fire tolerant and may benefit fromprescribed burning. It commonly produces a moreabundant seed crop the year after a fire. The seasonduring which the fire occurs may determine the effects onthe grass. It typically will re-sprout after spring or fallburns, but does not recover as well after a summer burndue to typically higher fire temperatures at the soilsurface. Larger plants often do not recover due to highercrown temperatures especially when excessive thatch hasbeen allowed to build up, increasing fire temperatures.Pests and Potential ProblemsSeedlings are susceptible to damping off in cold wetweather, especially in December and January. Pre-treatingseed with a fungicide has been used to effectively reducefungal problems. Smut has been detected in purpleneedlegrass plantings, but is not typically a problem. Seedcan be affected by smut but this has not been veryprevalent. Rust can also be a problem in green houseseedling transplants but has not been a problem in fieldplantings.