blue oat grass

Growing and Caring for Blue Oat Grass (Helictotrichon sempervirens)

Sharing is caring!

If you are looking for an award-winning ornamental grass for your garden then you can consider Blue oat grass (Helictotrichon sempervirens). 

In 1993, this charming grass species won the Award of Garden Merrit at the Royal Horticul Society because of its showy appearance and hardy nature.

Blue oat grass is great for adding texture to your garden because it produces showy slender blue leaves that create a fountain effect in garden beds. The ornamental grasses will also add lots of contrast to your garden with their vivid blue-tinted leaves.

The perennial grass is non-invasive because it cannot spread through rhizomes and it is easy to control.

Gardeners love this well-behaved grass because it is pretty easy to grow and care for. In this guide, we are going to take a look at some great tips that will help you grow large clumps of grass that will enhance the appearance of your garden.

Plant Facts

Scientific nameHelictotrichon sempervirens
Common namesAvena sempervirens or Blue Oat Grass
Plant TypeOrnamental Grass
Height and Width1–5 ft. tall, 1–2 ft. wide
OriginSouthwestern Alps in France and Italy
Flower colorsBlue or brown/copper spike flowers with brown/ copper seed heads
Foliage colorBlue to green
Sun ExposureFull sun or partial shade with 2 – 6 hours of direct sun
Soil Type & pHAny well-drained soil including chalk, clay, loam, and sand as well as alkaline to neutral soils. 
Special featuresLow Maintenance, Suitable for containers and functional as ground cover, barrier, or border plant

What Does Blue Oat Grass Look Like?

This charming grass is mostly grown for its striking appearance. Blue oat grass plants are clump-forming species with long blue-green foliage that creates a soft spiky appearance. They can also produce whispy flowers that stand tall above the leafy green foliage.

The grass clumps will maintain their vivid blue tone for the most part of the year because it is semi-evergreen. During the cold deep winter season, the grass blades might die back. If the winter conditions are not too harsh, the leaves can stay green for the most part of the winter.

Where Does Blue Oat Grass Grow?

These specimen plants are native to Europe and they can grow in USDA zones 4 – 8. Because of its flexible nature, the grasses can be grown in a number of areas. 

They are often used in desert gardens and can be used as a filler plant or ground cover in garden beds. Some also use the showy plant to create interesting mixed containers.

How to Grow Blue Oat Grass

These ornamental grasses are pretty easy to maintain once they are fully established. But if you are growing them for the first time from seeds or through propagation then you should consider the following growing conditions.


Unlike most ornamental grasses, this grass doesn’t spread with rhizomes. To propagate blue oat grass, you will need to carefully divide the root ball. 

To do this, you can dig up the entire clump and slice the root system into two or three equal parts. This is usually done every four years and springtime is the best time to divide these grasses.

The grass does produce seed and can also be propagated from seed. This is, however, a tiresome process since the grass has a low germination rate.


You should take care to plant blue oat grass in well-draining soil because it doesn’t like bogged conditions and won’t survive cold winters if the root ball stays wet when it is colder.

This plant is quite flexible in terms of soil. It prefers moist soil and can take well to sandy to heavy clay soil types. It will also grow in alkaline to acidic soil types and, even though the grass can handle poor soils, they prefer rich and fertile soil types.


You only need to prune back blue oat grass once a year. This is usually done during late winter. Simply grab all the old foliage and clip it off with a hedge trimmer or cutting shears. Snipping away the old foliage will help the new growth flourish.

How to Care for Blue Oat Grass

If you want blue oat grass to grow healthy and strong then it is best to plant it in a suitable location with the right soil and watering conditions. 

Here is a quick blue oat grass care guide that will help you keep these grasses healthy.


Blue oat grass is drought tolerant and its pronounced blue hue is at its brightest during dry or drought conditions. But the grasses grow most vigorously if they are kept moist.

It is best to water your grass regularly during the growing season so it can quickly develop. Watering should be reduced as the temperatures decline because the roots will die if they are kept moist during the cold winter. For pronounced coloring, you can also water sparingly once the plants matured.


The cool season grass grows best in a full sun position with lots of direct sun. It can tolerate partial shade positions but offers better visual interest in full sun positions because the foliage color will be more pronounced.

These grasses won’t grow well in shaded positions and are likely to flop over if they are grown in the shade.

Temperature and Humidity

These beautiful plants prefer low humidity and cool conditions. They can tolerate extremely cold temperatures of up to -25 degrees F but, even though they are drought tolerant, they won’t survive in extreme heat conditions.

These grasses are also flexible in terms of humidity since they can survive extreme dry spells or grow well in moist soil with lots of humidity in the air.


Blue oat grass botanical species generally don’t need to be supplemented with fertilizers because they can tolerate poor soil conditions. The grass will also grow well in rich soil with lots of fertilizer or organic matter.

Pests and Diseases

These grasses usually don’t struggle with pests or diseases. Gardeners might, however, encounter the following issues with these wonderful plants.

Foliar Disease

If the grass is grown in the shade with lots of moisture, it can become vulnerable to foliar diseases. The best way to avoid this is by planting it in the sunlight or by reducing the soil moisture levels a bit.

Crown Rot

If the plants are grown in bogued or waterlogged conditions, they will also develop crown rot. This is why it is so important to establish the plants in well-draining soil.

Rust Fungus

Rust fungus can also appear on the leaves if the plants are grown in high humidity conditions or if sprinklers keep wetting the leaves.

Blue Oat Grass Companion Plants

The beautiful blue foliage of this plant can be used to accentuate or complement other ornamental plant species.

Gardeners love to pair the cool season grass with other grasses because this will make the blue color of the leaves stand out even more.

You can also grow this striking plant with its arching stems alongside ornamental plants like dwarf blue spruce, juniper, butterfly bush, turtleheads, or sedum autumn joy.

Check this guide to see more blue oat grass companion plants.

Blue Oat Grass Landscaping Ideas

Blue oat grass can create year-round interest in your garden and there are lots of different ways to use this finely textured plant in your landscape. Here is a quick look at some creative ways to use the decorative plant.

Rock Gardens

The spiky leaves of this plant are perfect for adding lots of interest to a rock garden. You can place clumps of these showy grasses behind or alongside large boulders or grow them in rows or hedges alongside gravel walkways. The blue-tinted leaves will compliment the natural rocky hues of these types of landscapes.

Water Gardens

These perennials can tolerate lots of moisture and are the perfect species to grow around ponds or other types of water features. The fountain-like effect and blue leaf tone are perfect for creating a lush watery effect around water features.


These beautiful plants can also grow well in a container. If you do choose to plant it in a container then you should be careful to ensure proper drainage and it is best to grow it in potting soil.

The blue foliage will look rather striking as they arch out of a round container to form a showy fountain effect.

Common Varieties and Cultivars

There are a couple of different cultivars or varieties of blue oat grass. Here is a quick look at the most common cultivars of this low-maintenance plant.

  • ‘Sapphire’
  • ‘Saphirspudel’ or ‘Sapphire Fountain’


Blue oat grass is a terrific ornamental grass to add to your garden space if you want to create lots of vertical interest in your spaces. The green-blue hue of these stiff grasses can complement natural rocky features as well as other ornamental plant species.

We hope that you enjoyed our growing guide and that it helps you grow healthy and strong decorative grasses that will offer lots of garden merit.


Reference List

WSU Clark County Extension PNW Plants – Blue Oat Grass –

Susan Mahr, University of Wisconsin – Blue Oat Grass, Helictotrichon sempervirens –

Edward F. Gilman – Helictrotrichon Sempervirens Blue Oat Grass –

North Carolina Extension Gardener Plant Toolbox – Helictotrichon sempervirens –

University of Illinois – Ornamental Grass – Blue Oat Grass –


*image by Sergiosk/depositphotos

Scroll to Top