Which grasses should I plant?

Delicate green seedheads of Tufted Hairgrass

tufted hairgrass

Planting grasses (seeds, plugs or plants) is a quick and fairly inexpensive way to establish cover on bare, disturbed ground. Figuring out which species are adapted to your site is worth your time to assure good establishment and to prevent using a species that is inappropriate.

green bunchgrass with numerous fluffy white flower stalks

prairie junegrass

Selecting the most appropriate native grasses for your site can be challenging! Montana has 236 native grass species and numerous non-native species. 

Unfortunately some non-native species are aggressive and invasive and these undesirables are often planted by unwitting landowners. It is surprising how many of these are included in grass seed ‘mixes’.

How do we determine if a species is desirable?
Learn to identify grasses in your local area. Identify both native and non-native species present on your site. Examine your site conditions and select species appropriate for that site.

Grass identification can be difficult and usually requires the inflorescence (flower-like structure) of the grass to be present for correct id. Here are a few options for determining what grasses you have on your property:

single green bunchgrass plant of Indian Ricegrass with delicate cream colored flowers

Indian ricegrass

    • use the “Montana Grasses” app
    • take a sample to your extension service agent
    • find a willing botanist to assist

Chances are you have weedy grasses on your site as well as desirable species. Knowing what species you are dealing with is important. Here are some examples of invasive grasses in Montana according to the Center for Invasive Species and Ecosystem Health:

drooping seedhead of Canada Wildrye

Canada wildrye

Weedy grasses invade and colonize disturbed sites where they freely reproduce and thrive, outcompeting native species. Not only does this devalue land but creates serious eradication challenges when we attempt to restore native grasslands.

Whether or not we can truly restore a native grassland to its former condition is a subject of debate for another day, but leaving sites to be overtaken by weedy species is perhaps one of the most serious ecological issues we currently face.

Once you have identified species present on the property determine tactics for reducing weedy species while increasing native species appropriate for your site.  It may be impossible to totally eradicate weeds without serious damage to soil. Tactics for reducing weeds might include hand-pulling, bio-controls or herbicides.

Can native grasses be weedy? Yes, when introduced to different conditions than they normally exist in.

picture of Blue Grama grass 'eyebrow' seedheads

blue grama

  • A drought tolerant native grass may reseed like crazy when introduced to an irrigated site. (e.g. prairie junegrass)
  • A rhizomatous (spreads by underground stems) grass (e.g. sweetgrass) may take over an entire area if the soil is moist and comprised of organic matter. In the wild sweetgrass would be restricted by the size of the moist meadow in which it lives. In a garden it could become invasive.

 

It’s all about ‘right plant, right place.’ It’s an old adage but it’s still true.
Ideally replicating the native grass palette already in place is optimal for the ecosystem, plant health and local fauna. Right plant, right place!

delicate drooping seedheads of Richardson's Needlegrass

Richardson’s needlegrass

Assess the climactic conditions on your site. Is it sunny, shady, moist, dry, sloped? Keep in mind conditions may have changed due to construction, soil disturbance, compaction, removal of forest canopy and vegetation, etc… and you may be dealing with an altered landscape that may have difficulty supporting species that once grew there.

delicate white flowers on 6-10 inch green stems of Sweetgrass

sweetgrass

Next select species appropriate for your site. Match growing conditions. Use a mix of grasses already in the area. Naturalistic plantings include a mix of grass species and forbs (wildflowers and herbaceous plants).

Examples of native grass species in northern Rocky Mountains:

Examples of native grass species in northern Rocky Mountains:

Achnatherum (Oryzopsis) hymenoidesindian ricegrassmediummoderatefullsandydrought tolerant, short-lived, ornamental
Aristida purpureapurple threeawnshortmoderatefullsandyeasy to establish, warm season grass
Bouteloua gracilisblue gramashortlittlefullsand to silty-loamdrought tolerant, moderate establishment
Bromus marginatus (carinatus)mountain bromemediumhighfull to part sunsilty-loam to clayshort-lived, rapid establishment, keep moist
Calamagrostis rubescenspinegrassmediummoderatepart to full shadesilty-loam to clayrhizomatous, understory in coniferous forests
Danthonia unispicataone-spike oatgrassshortmoderatefull to part sunsand to claymoderately easy establishment
Deschampsia cespitosatufted hairgrassmediumvery highfullsilty-loam to clayvery moist sites
Elymus canadensis canada wildryetallmoderatefullsand to silty-loamrapid establishment, short-lived, moist sites
Elymus glaucusblue wildryetallmoderatefullsand to silty-loamrapid establishment, short-lived, good for stabilization
Elymus lanceolatus aka Agropyron dasystachyum)thickspike wheatgrassmediumlittlefullsand to clayrhizomatous, drought tolerant, short-lived
Elymus (Agropyron, Pascopyrum) smithiiwestern wheatgrassmediummoderatefullsilty-loam to claydrought tolerant, long-lived
Elymus trachycaulus aka Agropyron caninum, Agropyron trachycaulum)slender wheatgrasstallhighfullsand to claymoderate drought tolerance, rapid establishment, short-lived, good high elevation species
Festuca campestrisrough fescuemediummoderatefull to part sunsilty-loam to claypriries and open woods, does not tolerate trampling
Festuca idahoensisIdaho fescueshortlittlefullsilty-loam to clayslow establishment, moderate drought tolerance
Hierochloe odorata (Anthoxanthum hirtum)sweetgrassmediumvery highfullsilty-loam to clayrhizomatous, wet meadows
Hordeum jubatumfoxtail barleyshortlittlefullsand to clayeasy to establish, good for disturbed areas, awns problematic for pets
Koeleria macrantha, Koeleria cristataprairie junegrassshortlittlefull to part sunsandydrought tolerant, early season
Leymus cinereus, aka Elymus cinereusgreat basin wildryetalllittlefullsilty-loam to clayspring moisture followed by dry, slow establishment
Phleum alpinummountain timothyshorthighfull to part sunclayshort-lived, prefers poorly drained mountain meadows
Poa secundaSandberg bluegrassshortlittlefullsand to claydrought tolerant, early season, slow establishment
Pseudoroegneria spicata, aka Agropogon spicatumbluebunch wheatgrassmediummoderatefullsilty-loam to claydrought tolerant, moderate establishment
Stipa (Hesperostipa) comataneedle and threadmediummoderatefullsand to silty-loamdrought tolerant, long-lived; long awns problematic for pets
Stipa nelsonii (Achnatherum) nelsoniiColumbia needlegrassmediummoderatefullsilty-loam to claydrought tolerant, moderate establishment
Stipa (Achnatherum ) occidentaliswestern needlegrassmediummoderatefull to part sunsilty-loam to claydrought tolerant, long-lived
Stipa (Achnatherum) richardsoniiRichardson's needlegrassmediummoderatefull to part sunsilty-loam to claydrought tolerant, long-lived, awns problematic for pets
Stipa (Nassella) viridulagreen needlegrassmediummoderatefullsilty-loam to claydrought tolerant, moderate establishment

Not all species work in all places – right plant, right placeKnow what type of site each species needs.

Once you know what species are appropriate for your site and have dealt with weeds, where can you obtain grass seed, plugs or plants?

field of tufted Rough Fescue grass

rough fescue

When you check out seed companies and look for native grass seed you will often find that they offer cultivars of natives – plants selected for desirable characteristics that can be maintained by propagation. This is done through selection, hybridization, and genetic modification but the thing to remember is that a cultivar has a particular trait that it has been replicated through propagation. For example, a grass may be selected for its blue color, or it’s ability to produce lots of seed, or it’s ease of establishment. These traits may or may not be desirable.

A cultivar is designated by a word or several words in quotation marks that follow the botanical name, for example: Pseudoroegneria spicata ‘Secar’ or a list of cultivars following the plant description: Secar, Goldar, Whitmar.

blue-green foliage of Idaho Fescue bunchgrass

Idaho fescue

There is ongoing debate over the use of cultivars. My preference is to avoid them. They lack genetic diversity and impact the gene pool in the wild. Their homogeneity tends to look unnatural and there is concern over their value to wildlife that has evolved over time with a genetically diverse population.

On the other hand it may be difficult to locate seeds of native grass species.

One option is to collect your own seed. If you don’t have time to do that, select native species and create your own mixes. Keep in mind you only need small quantities of small seeds and larger quantities of big seeds. Most seed companies will provide the number of live seeds per pound and seeding rates for pure stands.

The Montana State University Extension publication Revegetation Guidelines for Western Montana may be helpful.

Some companies that sell native grass seed:

http://www.westernnativeseed.com/grasses.html
http://www.graniteseed.com/products/seeds/grasses-and-grasslike-species
http://stevensonintermountainseed.com/devsiseed/
http://derbycanyonnatives.com/seed/
http://www.bfinativeseeds.com/grasses.aspx

Let me know if you have another favorite so I can share the info!

short bunchgrass with furry orange to creamstems

one-spike oatgrass