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| ## tall mannagrass {#tall-mannagrass .Title-Header}                   |
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| *Glyceria elata* (Nash ex Rydb.) M.E. Jones                           |
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| Plant Symbol = GLEL                                                   |
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Contributed by: USDA NRCS Plant Materials Center, Corvallis, Oregon

##### Alternate Names {#alternate-names .Header-3}

##### Another common name is fowl mannagrass. It is now classified as the same species as the more widely distributed *Glyceria striata* which has similar common names.

##### Uses {#uses .Header-3}

Tall mannagrass is a rapidly establishing native species suitable for
restoration of swamps, the edges of marshes, ponds, and streams, and
other wetland plant communities where an herbaceous understory is
desired. It has versatility for use along creeks and ditch bottoms where
exposure may vary from full sun to dense shade, thereby improving soil
stability beyond the use of woody plants alone. Where this species
dominates, herbage production is high. Palatability of *G. striata* is
rated good to very good for cattle and horses which consume both flower
stems and leaves. It is rated fair to good for sheep which tend to use
only the leaves. The seed is food for waterfowl and birds while the
foliage and tall stems provide good wildlife cover. Foliage is
seasonally grazed at a light to heavy rate by deer, muskrat, and bears.
Elk can make minor use of it as well. Tall mannagrass may be applicable
to seeding mixtures targeted to improve species richness and exclude
reed canarygrass (*Phalaris arundinacea*) prior to its invasion. It is
occasionally planted as an ornamental in and around backyard
ponds.![](media/image3.jpeg){width="2.801388888888889in"
height="4.154861111111111in"}

##### Status {#status .Header-3}

Please consult the PLANTS Web site and your State Department of Natural
Resources for this plant's current status (e.g. threatened or endangered
species, state noxious status, and wetland indicator values).

##### Description and Adaptation {#description-and-adaptation .Header-3}

In the Pacific Northwest, tall mannagrass is a long lived, cool season
perennial bunchgrass with somewhat succulent stems (culms) that reach a
height of 100 to 180 cm. The form is erect, robust, and clumpy despite
the production of slow growing rhizomes or underground stems. Rate of
spread may vary among populations. Leaf blades are soft, ribbon-like, 6
to 12 mm wide and 15 to 25 cm long. The flowerhead (panicle) is loose,
broad, pyramid-like, and 8 to 27 cm long with spreading and drooping
branches. Populations previously described for *G. striata* include
plants that are shorter and tougher with smaller leaves (2 to 5 mm wide)
and flower heads that are more closed. *G. elata* was primarily confined
to the western states, but as *G. striata*, it occurs across most of
North America.

*Key to identification:* Physical differences described between tall
mannagrass and *G. striata* are inconsequential because they are now
listed as the same species. Tall mannagrass can be easily confused with
reed mannagrass (*Glyceria grandis*) which has smoother leaves and lack
its slightly rough texture. Others mannagrasses are easier to
distinguish, but a botanical key should be consulted.

*Relative abundance in the wild:* Seed ripens in July or August and
retention within the flower head is fair to good. Collections can be
readily made along wet forest road ditches, but access can be difficult
along streams or in denser, swampy brush where this species is commonly
found.

*Adaptation:* Tall mannagrass widely occurs in bogs**,** seeps, wet
woods, thickets or swampy areas, shaded ditches, and along or in
streams. It may occasionally be found growing in full sun on summer damp
soils as well as in standing water. Reportedly, this species is best
adapted to freshwater, semi-aquatic habitats (*G. elata*) or those that
are irregularly to seasonally flooded and saturated for up to 25 percent
of the growing season (*G. striata*). However, local plants have thrived
and flowered under continuous inundation (1-10 cm) for several years.
Tall mannagrass tolerates open areas but prefers shady habitats. It may
occur as single plants, small colonies, or larger stands that dominate
the understory of ash swales as well as willow, aspen, and other wetland
forest or shrub communities. Soils range from organic to mineral with a
pH of 4 (acidic) to 8 (slightly alkaline). This species does not
tolerate salinity and needs moderately good fertility. This species is
very shade tolerant, similar to reed mannagrass, yet it can be grown in
full sun to produce substantial seed.
![](media/image4.jpeg){width="1.4159722222222222in"
height="1.9805555555555556in"}

##### Establishment {#establishment .Header-3}

The presence of seed dormancy, if any, may vary among populations. Seeds
can germinate within 2 to 3 weeks without treatment but 14 to 30 days of
cold moist stratification (moist pre-chilling) has resulted in faster
but not necessarily higher germination rates. Others report the need for
150 days of stratification in cold water. Fall sowing is preferred if
dormancy is known or uncertain. Seed hulls readily detach but removal is
unnecessary. There are approximately 1,600,000 seeds per pound with
hulls intact. A seeding rate of 1lb pure live seed per acre will result
is about 37 live seeds per square foot. Seeding rates depend on methods
used, objectives, and site conditions.

##### Management {#management .Header-3}

Management considerations for utilization of *G. striata* by livestock
may predictably apply to tall mannagrass. Sites where it occurs are
typically too wet for grazing when the herbage is most succulent.
Therefore, access must be deferred until late in the season when soils
are drier and quality has declined somewhat. Tolerance to fire and heavy
grazing is not well documented. Tall mannagrass can be grown for seed on
upland sites with medium to fine textured soils if regular irrigation is
applied in summer and fall.

##### Environmental Concerns {#environmental-concerns .Header-3}

Some strains or populations of *G. striata* may contain cynogenetic
compounds. Cyanide poisoning from it as well as reed mannagrass has been
reported in cattle. Because tall mannagrass is now the same species or
closely related, caution is advised for livestock utilization. Likewise,
plant diseases that infect *G. striata* may apply to tall mannagrass.
This includes the fungal pathogens *Epichloe glyceriae* which causes
floral castration and *Ustilago striiformis*, better known as stripe
smut. Fungicides may be needed for control. Consult with your local
Extension Service agent, plant disease control handbook, or other
experts for advice. Other species of mannagrass are described as weedy
in certain crops or wet areas, but concerns for tall mannagrass are not
widely known.

##### Cultivars, Improved, and Selected Materials (and area of origin) {#cultivars-improved-and-selected-materials-and-area-of-origin .Header-3}

Seed sources and plants are regularly available throughout much of the
species natural range within the United States.

##### Prepared By:  {#prepared-by .Header-3}

*Dale Darris*, USDA NRCS Plant Materials Center, Corvallis, Oregon.

##### Species Coordinator:  {#species-coordinator .Header-3}

*Dale Darris*, USDA NRCS Plant Materials Center, Corvallis, Oregon.

##### Edited: 21mar2006 jsp, 17sept2008 dcd; 080919 jsp {#edited-21mar2006-jsp-17sept2008-dcd-080919-jsp .Header-4}

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

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