Big Bluestem – A Big Grass With Big Benefits

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Big Bluestem Identification and Physical Description

This tall perennial grass that is blueish green during the Spring and Summer, and eventually turns to gold/brown tan.  By August it should be reaching its maximum height for the growing season, which in optimum conditions (full sun, moist soil) should be 8-10′.

Stalk / Stem

Very erect and large, the round stalks (culms) of Big Bluestem all emanate form a central clump. The stalks aren’t really noticeable until mid-Summer when they rise above their lowest leaves.

Leaves

Leaves are long and slender (linear shape), being only 1/2″-1″ across but 10″ long or more.  They wrap around the stalk by more than 50% of the stalk diameter. The lowest leaves are really long, perhaps 36″, but get shorter as they ascend the stalk.

Flower

The flowers of Big Bluestem are racemes of paired spikelets that occur along the upper stems of the stalk.  The top of the stalk will split into 3 smaller stems, each containing dozens of spikelets.  The color is reddish-purple when blooming.  The color will change to a golden brown in Autumn.

Root

Roots of Big Bluestem consist of short rhizomes that go a couple inches deep, and fibrous roots that can extend 10′ deep in the soil.  Most of the root mass is concentrating in the top 1-2′ of the soil.  Interestingly, recent studies are suggesting that the deep roots don’t seem to be that important for water uptake.  So perhaps the extremely deep roots serve another primary purpose?

Big Bluestem throughout the growing season

Although everyone can give a description of Big Bluestem, you really need to see it through four seasons to appreciate it. It emerges from the ground in early Spring, just looking like a lush green ornamental grass. Quickly it will grow, with it’s lower leaves reaching several feet tall by the start of Summer. And that is the point when the main stalks (culms) will rise from the clump to reach the large heights o 8-10′ tall. By September or late Summer, it is still mainly green, but starting to show hints of bronze. And finally by Fall, it is a gold-tan or bronze color. The stalks will persist into Winter, but may fall down if there is very heavy wet snow, storms, or from animals.

As the image above shows, by late Spring you will have tall leaves roughly 36″ long that arch downwards. As summer progresses, this clump will have the stiff culms shoot upwards. By late fall / winter, many of the leaves will have laid down but the stalks will persist for sometime, usually into January/February. For reference, the Spring picture was taken on 26JUN, the Summer picture was in early August 14, and the Fall picture was on September 27th.

Growing Conditions for Big Bluestem

Big Bluestem grows best in full sun and slightly moist soil.  It can take dry conditions also, but may not be as tall and vigorous.  It is quite versatile in that it can grow in almost any soil type, from clay to loam, and even slightly sandy.  This was the most dominant prairie grass for it size and versatility. 

How to care for Big Bluestem

If you grow this in conditions that it prefers (full sun, moist soil) then you will have virtually no problems growing healthy plants.  It requires basically no care.

Maintenance

In Spring when insects are waking up, you can cut down and remove the stalks/foliage from the previous season.  You can do this earlier, however there may be beneficial insects wintering inside the large stalks.  So, I always suggest waiting until Spring temperatures have warmed sufficiently to where any larva would have emerged.

Growing from seed

Growing Big Bluestem from seed is incredibly easy.  The first year it will only grow to several feet high, but by the second or third year it should be topping 8-10′, assuming it is in it’s preferred growing conditions. One of the key factors in getting it large quickly is to transplant it into larger pots progressively, or transplant into the ground by mid-Spring. The sooner it gets to it’s final location, the better. However this isn’t always easy to do if you miss the Spring planting window. If outdoor temperatures get consistently hot (90F+) for days on end, then I prefer to keep the plant in containers until late summer or fall, at which point I’ll plant them. Just an FYI – you can plant perennials into winter.

The optimum temperature for Big Bluestem to grow has been found to be 25 Celsius^[5], or 77 Fahrenheit.  So if temperatures are below or above this it will grow slower.  How much slower will depend on the temperature.

Germinating Big Bluestem Seeds in pots or containers

1. In late winter or very early Spring, fill 4″ (10 cm) pots with moist potting soil to 1/2″ (12 mm) from the top.
2. Pack the potting soil so that it isn’t loose, but slightly firm.
3. Sprinkle 5-10 seeds on top, and press them firmly into the soil
4. Sprinkle a handful of potting soil on top of the pot, just dusting the seeds.  I always make that I can still see some of the seeds, so that they are partially covered.
5. Keep moist until germination.

Also, you can winter sow Big Bluestem.  Just repeat the process above, but set the seed tray outside but covered.  Similar to the instruction in this video.

Below is a picture of a Little Bluestem seedling, however the seedlings are almost indistinguishable from Big Bluestem.

Direct Sowing

You can also direct sow Big Bluestem in Autumn too.  Just use a metal rake to disturb the top 1/2″ of soil, sprinkle seed in the area, and walk over it.  The force from your shoes pressing the seed in the soil should be enough to maintain good soil/seed contact.  Then, sprinkle a little bit of soil over the top to protect the seed from birds.

Purchase Seed

We have ordered a variety of native flower seeds from Everwilde Farms, which you can order right from Amazon through our link on our RECOMMENDED PRODUCTS PAGE. (We may earn a small commission when you purchase through our links, at no cost to you. This helps support our website.)

How to Save and Harvest Big Bluestem Seed

Once the seed head has turned brown and dried on the stalk for a week or two, you can collect them.  Store them in a paper bag for a few weeks in a cool dry environment to allow the seed to dry completely.  After this the seed can be stored for about six months and still be mostly viable.

Landscaping

This plant may not be sold as an ornamental, but it should be.   The blue green color is gorgeous during the Spring.  And the late Summer bloom is very pretty too.  As stated in the intro, when this plant sways in the breeze it is almost hypnotizing.

So, you can use this plant as a border, in a wildflower garden, or as an individual accent in a flowerbed.  Just make sure you give it some room per our reference table in a flowerbed.  We have several specimens in our backyard micro-prairie.  These grasses help provide support for other species that can droop over under their own weight.  You can learn how to make your own small prairie by clicking below.  It really is a great way to bring on the wildlife!

Self-seeding

Does Big Bluestem self-seed? In short, yes, it will, but not too bad. I have had about 4-5 volunteers that have grown to maturity in my backyard wildflower area over the last 7-8 years. So, it will self-seed, but not to a huge degree.

Fauna

This plant is host to many insects, and provides forage for other insects.  At least 12 different grass hoppers and many different skipper moths feed on the foliage^[4][6].  A partial list of Skippers caterpillars that feed on the foliage is below.

• Byssus Skipper
• Cobweb Skipper
• Dakota Skipper
• Delaware Skipper
• Dusted Skipper
• Ottoe Skipper

Additionally, Big Bluestem seeds are eaten by birds (particularly smaller songbirds).  Furthermore the grass can provide cover to small mammals and other birds.  This is really a great plant to grow if you want to attract wildlife.

Find more native grasses here