The Complete Guide for Blue Oat Grass (Helictotrichon Sempervirens) Care

The Blue Oat Grass, otherwise known as the Helictotrichon Sempervirens or Christmas Rose ‘HGC Jacob’, Bear’s Foot ‘HGC Jacob’, Black Hellebore ‘HGC Jacob’, Brumal Rose ‘HGC Jacob’, Christmas Plant ‘HGC Jacob’, Christopher’s Herb ‘HGC Jacob’, Christ’s Herb ‘HGC Jacob’, Clove-Tongue ‘HGC Jacob’, St Agnes’ Rose ‘HGC Jacob’, Helleborus niger ‘Jacob’ PP17799, is a rather well known perennial plant by gardening enthusiasts around the world.

Best known for its low maintenance and moderate growth, this perennial will likely liven up your house (or garden) with its blue-green colored leaves. But, only if you learn how to take proper care of it for it to thrive.

Fortunately, this is exactly what we’ll cover in this Blue Oat Grass Care Guide. So let’s dive in.

The fundamental caring guidelines for every Blue Oat Grass can be summed up into the following:

  • Water: The Blue Oat Grass needs increased watering in hot weather but reduce amount when established.
  • Light: Keep your Helictotrichon Sempervirens in an environment where it can receive full sun on a daily basis. 
  • Soil: Make sure to keep the Blue Oat Grass in soil with moist but well-draining properties, so ideally, one that is made of loam, chalk, and clay.

And that’s practically it! If you keep these three factors in check, your Blue Oat Grass will likely have all it needs for it to survive and even thrive.

Blue Oat Grass flowers

Scientific / Botanical Aspects

In botanical terms, the Blue Oat Grass belongs to the Ranunculaceae family, the genus Helleborus and the species Niger, hence its scientific (or botanical) name Helictotrichon Sempervirens (hel-ik-toh-TREE-kon sem-per-VY-renz).

As with other Helleborus’s, the Blue Oat Grass is a semi-evergreen plant, which means it will shed its leaves but only for a short period of time.

Growing Region

The Blue Oat Grass is a plant native to the alpine and open woodlands in central and southern Europe.

As a rule of thumb, we recommend to always keep in mind your plants’ native region and environment, since these are the conditions that your Blue Oat Grass is most accustomed to, thus where it can most favorably.

With this in mind, the Helictotrichon Sempervirens will be most used to the heat zones in the 5 – 9 region, as the plant hardiness level falls between 3a, 3b, 4b, 4a, 5b, 5a, 6b, 6a, 7a, 7b, 8b, 8a and the ideal climate zone is between 3, 4, 5, 6, 7, 14, 15, 16, 17.

Growth and Size


In terms of size and growth, the Blue Oat Grass is a relatively moderate grower, which makes things somewhat easy for any plant enthusiast.


But, how big does the Blue Oat Grass actually get? What should you expect in terms of size? Let’s dive right in…

The Helictotrichon Sempervirens can grow up to 6″ – 8″ (15cm – 20cm) in 6″ – 8″ (15cm – 20cm) and 1′ (30cm) in 1′ (30cm). 

These dimensions make the Blue Oat Grass a relatively medium perennial compared to others, so it’s best to keep this fact in mind since it will affect where you want to keep yours at home.

Also, expect it to grow in a wonderful rounded shape, which is something worthwhile to remember when making your garden landscape plans.

This is why experts recommend keeping an area of approximately 12″ (30cm) free so the Blue Oat Grass can spread to its best extent.


In terms of watering, the Blue Oat Grass is a fairly complicated plant to take care of.

This is mostly because it has a not so straightforward watering schedule and somewhat irregular watering needs.

Specifically, most experts agree that the Helictotrichon Sempervirens needs increased watering in hot weather but reduce amount when established.

Which is why it is considered a plant with relatively average needs in terms of water. 

Blue Oat Grass care


As a rule of thumb, you should remember to keep your Blue Oat Grass in soil with moist but well-draining characteristics, as these will guarantee the right conditions for your plant to grow and thrive. 

When you consider this, this is why you should aim to choose soil that has good drainage properties to keep the right moisture levels at all times. 

However, in our experience, the best solution to knowing the right amount of water for your Blue Oat Grass is with the ‘thumb’ technique. Basically, you insert your finger into the soil, and based if you feel the soil moist or dry, you determine if it needs any water, which is the most appropriate way to go about watering your leafy friend.

Soil Mix

As mentioned earlier, the Blue Oat Grass prefers to have soil with good drainage properties at all times, reason why you need to make the soil mix out of loam, chalk, and clay.

This is why most experts agree that the Blue Oat Grass requires soil with high organic matter, which will give you the right conditions it needs.

In addition to this, expert gardeners recommend having preferably neutral to alkaline soil.

Light and Exposure

In terms of light & exposure, the Blue Oat Grass requires full sun in order for it to thrive under the right conditions. 

Most experts agree that this perennial will do well as long as you keep it in partial sun to shade, and it will be able to grow properly.

Specifically, we recommend that you place your Helictotrichon Sempervirens in from full or deep shade (no direct sunlight or at most 2 hours per day), to little to partial shade (only 2-6 hours of direct sunlight a day), to dappled or moderate shade (under other plant’s canopy).


Being a semi-evergreen plant, the Blue Oat Grass will shed its leaves but only for a short period of time.

But, you can expect it to have its ‘prime-time’ during the spring (early), and during the winter.


You can expect your Blue Oat Grass to flower around the winter and in the spring months from January to March (winter) and from April to June (spring).

The Blue Oat Grass produces some beautiful brown, or purple/lavender, greenpink, and white flowers around this time of year.


The leaves from the Blue Oat Grass have a beautiful blue-green color during most of the year.

In particular, they have a compound (pinnately, bipinnately, palmately) arrangement with a alternate organization in its leaves.

Blue Oat Grass up close

Attracts, Tolerance and Resistance

The Blue Oat Grass is well known for its tolerance to animals like deer, so don’t worry if any of these come along, your Helictotrichon Sempervirens will be fine.


How should you then organize your garden to include your new Blue Oat Grass? Here are some recommendations by expert gardeners.

Most Helictotrichon Sempervirens owners agree that this perennial will look great in most mediterranean, contemporary and rustic gardens of all types. 

Other owners consider that they complement well most gardens of informal and cottage, and in prairie and meadow styles. 

In particular, the Blue Oat Grass’s best location within your garden is in patio and containers, beds and borders, ground covers, and in underplanting roses and shrubs, others use it for landscaping in a mass planting, ground cover, erosion control, border, firescaping/fire wise, green roof, or a rock garden.

Companion Plants

Blue Oat Grass’s do well with some other plants beside it. One good companion plant is the Berberis, which will pair up nicely with your leafy friend.

Others consider that a nice Weigela will work well too, so choose whichever you find works best for you!


Even though we covered a lot of care information for your Blue Oat Grass, remember the basics: sunlight, soil and water, as these should be enough to grow a healthy plant at home.

Martin Duran

Hey y'all! My name is Martin Duran and I am from Cali, Colombia. Since 2018 I have been learning about plants and how to take care of them. Here's is my journey... “The clearest way into the Universe is through a forest wilderness.” ― John Muir

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