Blue Oat Grass: How to Care for Blue Oat Grass

If you are finding a standing-out grass species then blue oat grass would a wonderful choice.

This plant features blue-green grass shoots with non-invasive behavior. Its clumps grow foliage during the spring and summer season but rarely self-seeds.

This grass does not take over the whole garden like most grass plants. In the winter or moderately cold climate, blue oat grass grows to become evergreen or semi-evergreen, meaning you can enjoy its beautiful blue-green foliage even when the growing season is gone. 

Additionally, in the summer, this grass produces tiny blue-green flowers bearing seeds that appear on the top of the foliage stalk in clusters called panicles. These seeds turn into brown plumage in the fall and look similar to oats.

This article is focused on blue oat grass – how to grow and care for this ornamental grass.

how to care for blue oat grass

Quick Guide

Common NameBlue oat grass
Scientific NameHelictotrichon sempervirens
Plant typePerennial grass
Mature Size2-3 feet taller and 2-3 feet wider
Sun ExposureFull sun 
Soil TypeDry, Average, well-drained soil
Soil pH6.5 – 7.5
Bloom TimeSummer
Flower ColorBlue
Hardiness Zones4 to 9 USDA (can be grown annual anywhere)
Native AreaEurope

How to Grow Blue oat grass 

Blue oat grass is one of the best ornamental grass for the garden because this plant is not invasive and requires very little care for its beautiful appearance. This plant only needs average dry moisture soil and adequate spacing for air circulation. 

The plant rarely self-seeds and requires occasional cleaning to remove its dead foliage. 

Spread a thick layer of mulch around the blue oat grass to avoid the growth of unwanted weeds.

This grass can grow in tough conditions and tolerate salt environments and urban pollution. However, it is not much tolerant to hot and humid climates as this is a cold-weather plant.

How to care for blue oat grass


This grass’s varieties also do not require much care and give blue-greenish look to the garden similar to blue fescue.  The only care they need is to occasionally remove unwanted weed-grown around them by hand or with a rake. 


Blue oat grass thrives in full sunlight, they are tolerant to partial shade but in too much shade they become leggy. Ideally, you should plant them where they receive maximum sunlight but get at least six hours of direct sunlight per day.


Blue oat grass prefers average, dry, well-drained soil. Too wet or soggy soil will lead to root rot which kills the plant. For this reason, heavy clay-like soil is strictly not recommended to use.

This plant can thrive in slightly alkaline to neutral soil. A soil pH level ranging from 6.5 to 7.5 is considered ideal. However, this plant can tolerate naturally salt soil and is not much affected.

If you find it hard to establish them in the soil garden. You should probably check the pH level of the soil. Usually, this does not happen, but if the pH level is not in the range, you can adjust the soil pH by mixing organic compost with the soil. 


Generally, blue oat grass varieties do not need water. It becomes drought-tolerant once get established. If your region gets average rainfall, it can manage to grow. It gets underground water, and usually, its upper soil looks dry. Avoid overwatering, it will cause root rot which destroys the whole plant. 

When the plant does not enough water its foliage becomes wilt and yellow.

Temperature and humidity

This ornamental plant prefers a dry and cold climate. The blue-gree foliage of blue oat grass for which it is famous is most visible in prominent dry conditions.

In the cold, the plant foliage becomes semi-evergreen and able to retain blue color through winter. In the hot summer, when it becomes too harsh on the plant then it may not show a blue-green hue or bloom flowers.


Generally, hardy and evergreen blue oat grasses do not need fertilization. If you plant them in good condition and take proper care.

However, the decision of fertilization depends on the condition and color of the foliage of the plant. If the foliage is healthy and green, it does not need to be fed. But if the plant does not produce enough leaves you should probably feed fertilizer.

If you find the plant’s poor growth is due to a lack of soil nutrients then you can use organic compost, leaf mold, and other biodegradable matter. If you want to use conventional fertilizer, then go with the 10-10-10 formula, which is typically recommended for ornamental plants. 

But, do not feed them too much because anything with excessive nitrogen will overproduce foliage and least flower, leading to leggy, poorly flowered plants.   

Pests and diseases

Usually, blue oat grass does not suffer from many pests and diseases. However, it may get rust in overly humid conditions or due to a lack of air circulation. You can plant a signal blue oat grass or make a whole row as a land space border. Give at least three feet of spacing between each plant. 

Pruning or Triming

Blue oat grasses are a low maintenance plant, but it’s important to occasionally clear its dead growth. You can easily pull out the dead foliage of the grass by using a hand and garden rake by combing in the clump of the grass and removing dry, old foliage.

In the winter, this grass goes dormant, you can trim foliage a few inches above the crown for good growth in spring. However, sometimes in the cold climate blue oat grass does not lose its blue-green hue. In this case, do not trim them and enjoy their beauty the entire season.  

Blue Oat Grass varieties

Helictotrichon Sempervirens ‘Sapthirspurdel’: This variety is very similar to the original blue oat grass. However, this cultivar is developed for a more pronounced blue-green color with long and thick shoots and can have a stronger tolerance for heat and humidity.

This variety is quite better than the conventional ones and has a longer life span. If you have this variety you can grow many more by dividing or getting a small clump of them from a nearby nursery. This variety grows better in the yard or garden due to its long and thick shoots.  

How to Propagate blue oat grass

Blue oat grass can be propagated from seeds or division. But, many gardeners find that this plant’s seeds germinate slowly. Also, growing from seeds sometimes does not work.

Nowadays, there are many cultivars developed for better foliage or to resist diseases. These cultivars are developed by cross-breeding varieties. If you try to propagate a new plant from these cultivar’s seeds chances are they do not grow similar to their parent plant. 

So, division is the best method to propagate this ornamental plant.

Usually, gardeners divide this plant every 3-4 years. Blue oat grass is a hardy, evergreen plant but it requires occasional trimming for neat and continuous growth.

How to propagate blue oat grass from division

The division is the most popular method to grow multiple plants. If you have a healthy and beautiful plant in the garden, pot, or container. You can grow multiple similar plants by using its long shoots.

Blue oat grass does not have long stems like many flower plants, but rather dense, clumps of foliage. 

For division, you need to choose a mature plant (at least one-year-old) with a size of about 6-8 inches.

To divide blue oat grass:

  • Take shade, a strong gardening shovel, or a spade. You need to dip up the plant with its root clumps.
  • Make sure you dip a large area to get whole root balls out from the ground. Ornamental plants have a substantial root system.
  • Pour water, and make the soil moist to easily dig the root balls. Gig grass with minimal root damage.
  • Try to remove soil from the root balls by using your fingers and water.
  • With the help of a shovel or spade, cut the plant’s crown into two or three parts in roughly equal size.
  • Plant one part of the division back to the original plant. And other parts in different locations where you want to propagate new plants.

How in propagate in container

Blue oat grass is ornamental grass that generally refers to thrive in large and open areas. But, you can grow it in a pot or container to decorate in the house. For this, make sure the pot has adequate drainage holes and well-drained soil. Place the pot where it gets direct sunlight.

But, plants that grow in containers may lack the nutrients to sustain them. While blue oat grass does not require fertilizer in the ground, in the pot or container you may need to feed them.   

Did I Miss Anything?

Now I’d like to hear from you: which tip from today’s post are you going to try first?

Or maybe, I didn’t mention your favorite blue oat grass growing tip. Either way, let me know by leaving a comment below right now.

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Thank you for reading 😀

Also, check these articles:

Best Foliage plants to grow in the garden for a wonderful look.