Learning To Grow Blue Oat Grass

Blue oat grass, Helictotrichon sempervirens [hel-lik-toh-TRY-kon, sem-per-VY-renz] is a semi-evergreen, cool-season, hardy, and showy ornamental grass and has distinctive blue leaves which enhances the look of your garden. 

Learn more about Landscaping with Ornamental Grasses

Belonging to the Poaceae family, Helictotrichon sempervirens is native to southwest and central European grasslands.

Blue Oat Grass growing in the landscapePin
Matt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0], via Wikimedia Commons

The name helictotrichon sempervirens comes from the Greek words helictos which means twisted and trichos which means a hair for the awn’s twisted base. 

The plant type is widely cultivated as a perennial ornamental ground cover grass.

Gardeners love the plants as it is also the recipient of the prestigious Award of Garden Merit of the Royal Horticultural Society.

It is a hardy plant type and is capable of handling temperatures down to 0° degrees Fahrenheit (-18° C). 

Since the plant has longer leaves, they flop ever and move elegantly with the wind and provide visual interest to rock gardens. 

The plant also has multiple options of use: you may use it as a single accent plant; try it in a container, or grow it in masses. 

In appearance, it is similar to blue fescue (Festuca Glauca) but it is slightly bigger in size.

 Helictotrichon sempervirens generally is known by the common name – Blue oat grass.

A popular cultivar is ‘Sapphire’ with deep blue foliage. It is also known by its German name ‘Saphirsprudel’.

Blue Oat Grass Care

Size & Growth

The blue foliage color of this cool-season, clump-forming, perennial grass grows in a mound of spikey grass and resembles the shape of a water fountain. 

In most cases, the plant type will also resemble a porcupine-like clump. 

And while other plants may lose their beauty when they flop over, the grass is liked for its clump-forming as it makes the garden appear more vibrant. 

Its long leaves typically grow up till 2′ to 3′ feet. 

The mound of blue leaves consists of spikelets of bluish-brown flowers perfect for adding elegance to the landscape. 

These flowers with bluish tint turn harvest gold in late summer to autumn. 

Most gardeners prefer mass plantings of the blue oat grass to increase the overall look of their gardens. 

It is also a less invasive option for the landscape as it doesn’t spread via stolons or rhizomes, like other perennial grass. 

It is an easy-care plant and makes the perfect fit as a container plant. It is evergreen in locations with mild winters.

Flowering and Fragrance

The bloom time of blue oat grass is somewhere between early summer and late spring. 

Tiny, blue-white flowers first begin to appear on seed heads of one-sided panicles in an oat-like cluster. 

The flowers are around 4″ to 6″ inches tall and have delicate, pointed petals with thistle-like and spiky centers. 

Throughout the fall, the blue oat grass maintains vibrant light brown flower color. 

The fall color gives a spectacular and eye-catching look to the plant.

Light & Temperature

Helictotrichon sempervirens is a cool-season, showy ornamental grass and grows in the full sun. 

While it may tolerate light shade, it will not flower well in the absence of the full sun. 

Even though the plant is well adapted to plenty of soil types, for the perfect steel blue color, grow it in well-drained, unenriched alkaline soil in a sunny place. 

The growth rate of the plant will definitely increase if you pay attention to its water needs, soil type, and light requirements.  

It is typically grown in USDA plant hardiness zones 4 to 8.

Watering and Feeding

The water needs of this low-maintenance plant range between dry and medium. 

This is a drought-tolerant plant and requires little care. 

As such, the plant doesn’t require regular fertilization.

Soil & Transplanting

The blue oat grass grows well in well-drained soil. 

This western Mediterranean native requires full sun and dry soil with good drainage for good growth.

Grooming: Should Blue Oat Grass Be Cut Back?

Blue oat grass is a low-maintenance grass but would require routine trimming. 

In late winter, cut back the old foliage of the clump-forming grass to 3″-4″ before new growth begins to emerge. 

In spring, pull away the old dead leaves to maintain a fresh look of the grass.

How To Divide Blue Oat Helictotrichon

This cool season grass is propagated by seed in spring and by division in early spring or autumn. 

When propagating by division, use a sharp knife or a spade after digging up the mother plant. 

In the following year, the plant should experience robust growth in the growing season. 

The separated plants are treated as a new perennial grass plant and planted at a new location. 

When growing from seed, place the fully ripe seeds of the plant in moist sand in a pot and cover with foil. 

To prevent mold growth, remove the foil at least once a day until seeds sprout.

Helictotrichon Sempervirens Pest or Diseases  

While the blue oat grass is not susceptible to pest attack, it can get rust, especially in humid climates. 

In poorly drained and moist soils, the plant is susceptible to crown rot.

Uses For Deer Resistant Blue Oat Grass

The bright blue color of this deer resistant grass makes it a perfect addition to rock gardens. 

The plant spreads slowly and is not considered invasive.

It grows as an accent plant, and looks great combined with blanket flower (Gaillardia), Russian sage (Perovskia), or Sedum ‘Autumn Joy’.  Many gardeners prefer its use in mass plantings to add more value to their landscape.

JOIN Our FREE Plant Care Newsletter 

By entering your email address you agree to receive a daily email newsletter from Plant Care Today. We'll respect your privacy and unsubscribe at any time.