Helictotrichon Species, Blue Oat Grass

Helictotrichon sempervirens

Family: Poaceae (poh-AY-see-ee) (Info)
Genus: Helictotrichon (hel-lik-toh-TRY-kon) (Info)
Species: sempervirens (sem-per-VY-renz) (Info)


Ornamental Grasses and Bamboo

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun


Grown for foliage


Foliage Color:



12-18 in. (30-45 cm)


12-15 in. (30-38 cm)


USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

Where to Grow:

Grow outdoors year-round in hardiness zone

Can be grown as an annual



Bloom Color:


Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Late Spring/Early Summer

Other details:

Unknown - Tell us

Soil pH requirements:

6.6 to 7.5 (neutral)

Patent Information:


Propagation Methods:

By dividing the rootball

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds


This plant is said to grow outdoors in the following regions:

El Sobrante, California

Groveland, California

Groveland-Big Oak Flat, California

Los Angeles, California

Martinez, California

Salinas, California

Santa Rosa, California

Denver, Colorado(2 reports)

Boise, Idaho

Evanston, Illinois

South Bend, Indiana

Louisville, Kentucky

Middle River, Maryland

Quincy, Massachusetts

Allendale, Michigan

Mason, Michigan

Whitehall, Montana

Reno, Nevada

Denville, New Jersey

Haddonfield, New Jersey

Enid, Oklahoma

Harrah, Oklahoma

Altamont, Oregon

Klamath Falls, Oregon

Pine Grove, Oregon

Portland, Oregon

Downingtown, Pennsylvania

Rowlett, Texas

Park City, Utah

Pleasant Grove, Utah

Riverton, Utah

Santaquin, Utah

Tremonton, Utah

Essex Junction, Vermont

Keller, Virginia

Bellingham, Washington

East Port Orchard, Washington

Ferndale, Washington

Palouse, Washington

Parkwood, Washington

Port Orchard, Washington

Valleyford, Washington

White Center, Washington

Beverly, West Virginia

Casper, Wyoming

show all

Gardeners' Notes:


On Apr 16, 2016, pjwin1951 from Allendale, MI wrote:

I am in zone 5b with heavy clay soil. The oat grass is doing well and is maintaining it's shape and color. It has shown no signs of being invasive and is one of the easiest plants in the garden to care for. I have not cut it back and only have to remove dead blades by hand or rake to keep up its appearance.


On Oct 29, 2015, coriaceous from ROSLINDALE, MA wrote:

This evergreen blue-foliaged grass is very beautiful where it does well. Around Boston, I see more plants performing poorly than performing well, though I agree that this does better here than the blue fescues, which don't last long.

This is a well-behaved clump former. Those who've written that it's an invasive spreader are confusing it with a different species such as Leymus arenarius, which is also sometimes called blue oat grass.

This is a cool-season grass that does not enjoy hot summers.
Full sun and good drainage are required.


On Jan 31, 2014, Rickwebb from Downingtown, PA wrote:

It is a reliable and handsome ornamental grass with soft, very blue foliage. I find it better than the smaller Blue Fescue grass that sometimes dies out or gets crappy. It is easy to dig up and it can be cut into sections with a sharp tool, though so far, in about ten years I have not had to divide and reset my three plants. I have never seen it self sow for over 10 years in my front yard in se Pennsylvania from its tiny flower heads. It stays blue-green for a long time or all season during winter, unless it is a really cold one. I cut the plant down close to the ground in March just before it regrows in early spring.


On Jun 24, 2013, LeafPeeper from Bonners Ferry, ID (Zone 6b) wrote:

I've grown this plant for years. I've tried a couple of methods to maintain it including cutting it back in late winter each year or raking out the dead blades in the spring and again in the fall. The advantage of the raking is that the structure of the plant is maintained, the blue blades remain and only the dead blades come out easily. I do cut the oat tips back and neaten up the plant after it blooms but I always try to keep the structure of the plant. It is not invasive here and is extremely easy care except for the slight maintenance a couple of times a year. It's a great plant!


On Jun 24, 2013, veronicadengler from Denville, NJ wrote:

Prickersnall, there are photos of Blue Oat Grass on the right side of the page. If you click on "click here to see all photos" you will see pictures of the seed head.

I don't think the plant needs any nutritional help to keep it blue. Mine is always blue and I rarely give it anything except mulch.

I am very surprised to see it labeled as invasive. I have grown it for about 10 years and have never seen it reseed itself. I have saved the seeds and started them indoors, with a low germination rate. I just use a lot of seeds when I want to grow more.


On Jun 24, 2013, prickersnall from Madison, WI wrote:

I hope I can post a question...2 in fact:

What does the seedhead look like, and is any nutritional helpful in promoting...or retaining...optimal blue color in the leaves ?

Thanks for any info.


On Feb 3, 2011, jpgreen from Roswell, NM (Zone 7a) wrote:

Will not tolerate clay even when kept dry.


On Jan 13, 2011, laughingswan from Kamloops, B.C.,
Canada wrote:

To the Mtngardener in Colorado, Helictotrichon sempervirens (blue oat grass) is strictly clump-forming. That means it does not grow by underground runners, or rhizomes. The plant forms a neat clump. It does not spread aggressively throughout the garden. It will, however, self sow, and you may find seedlings coming up elsewhere if the conditions are favorable. If what you think is blue oat grass has been growing unchecked in your garden, it isn't blue oat grass. Perhaps it was mis-labeled, and you actually have a different plant. Elymus (or Leymus), wild rye, is of similar color, but different form and does indeed spread aggressively. If you have doubts, refer to my favorite reference on the topic, "The encyclopedia of grasses..." by Rick Darke, or a local expert.


On May 15, 2010, borde from Whitehall, MT (Zone 4a) wrote:

I've had the plant about 8 years now, and it still looks lovely. We live in zone 4 and have an annual rainfall of 11" so like drought tolerant plants. This plant is supplied with extra watering by sprinkler, but not fussed over. I was surprised to hear that it was invasive, because in all that time we have had it it has only produced one natural offspring. I have never divided it because I have been wary of doing so and it never increases in width anyway. It's proabaly 2 feet wide and 36 " tall in bloom. Our soil is pretty unfertile decomposed granite; I occasionally add rabbit manure to the plants.


On Jan 13, 2009, Tim_in_Iowa from Underwood, IA wrote:

I have tried to grow this plant several times (Iowa) with no luck. It lives for about two months gradually deteriorating until it finally dies. In some cases I've provided plenty of moisture and others I've let it stay dry....same results. I was thinking maybe it was the summer heat but I see that someone in San Francisco is having the same problem.


On Dec 16, 2008, Illig1 from Redwood City, CA wrote:

In the San Francisco Bay Area, the blue oat grass that I see looks fresh and blue when newly planted, and then ages very poorly, very quickly, regardless of the conditions. After a short time, it is almost always overwhelmed by dying, brown foliage which ruins the looks of this plant.


On Dec 15, 2008, MtnGardener from Longmont, CO (Zone 5a) wrote:

Blue oat grass in 5b is a beautiful grass, but be warned it is HIGHLY invasive in good growing conditions.Would recommend planting in a large pot to control it's growth. We did not plant it in a large pot, didn't think anything could grow like that in our weather and ended up pulling it out as it spread unchecked through the garden. Will be planting it again in spring but this time in a large pot to control it's growth.


On Dec 23, 2007, jonaflatooni from Port Orchard, WA wrote:

In addition to the previous comments blue oats grass does nicely in combination with blue fescue and other ornamental grasses and is a bit taller than blue fescue which gives it a good contrast.

The blades are more crisp and upright with a bit more sharpness to the edge than blue fescue.


On Mar 6, 2005, northgrass from West Chazy, NY (Zone 4b) wrote:

I have only good things to say about this grass.
Beautiful blue-green foliage.
Nice, neat mound.
Keeps its good looks all season.
Nice size in the garden, never overwhelms.
Of course, like most grass, it is very easy to grow.


On Jul 3, 2003, stevenova from Newcastle,
United Kingdom (Zone 8a) wrote:

I have to agree that this is probably the best blue grass around for ornament apart from the equally superb Koeleria glauca.

Where I work, we have a large bed with various grasses including this one and it performs so consistently well (especially against the over rated blue festuca's) and never looks shabby.


On May 4, 2002, naturepatch from Morris, IL (Zone 5b) wrote:

Divides very easily. Tolerates part shade very well. Did not tolerate being flooded one year very well, but a snippet lived on to be divided into 5 clumps. Blooms in early May in zone 5. Nice blue green foliage. Very similar to blue fescue, but taller. One year the birds pulled all of the dead foliage out to use for nest material, but they ignored the blue fescue. Can't beat it for an ornamental grass.