Mature size & growth rate

How big does Big Bluestem (Andropogon gerardii) get?

Also called big bluestem, turkey foot grass, beard grass.

More about big bluestem

About Big Bluestem

Andropogon gerardii · also called big bluestem, turkey foot grass · flowering

Big bluestem is the iconic tall-grass prairie dominant of North America, reaching 1.5–2 m with striking blue-green foliage that turns fiery copper-red and burgundy in autumn. Its distinctive three-pronged seed heads — earning the name 'turkey foot' — persist through winter. Deeply drought-tolerant and wildlife-valuable, it is a foundation species of native and prairie-style gardens.

Mature size: 120–200 cm tall in flower; clumps 60–90 cm wide

Watch for — Flopping / lodging in rich soils: Excessive soil fertility or shade causes stems to grow too tall and fall over. Grow in lean, unimproved soil in full sun. Staking is rarely practical; relocating to leaner conditions is the correct solution.

Indoor size vs how big it gets in the wild

Big Bluestem stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward. Indoors and in a pot, expect 120–200 cm tall in flower. In the ground with no restriction it is a completely different plant — clumps 60–90 cm wide — which is why the pot, the light and the pruning matter so much for the size you actually end up with.

Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Growth rate and years to mature

Big Bluestem is a moderate grower. Realistically, expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Its feeding profile backs this up: do not fertilise. supplemental nutrients cause excessive height (up to 2.5 m+), flopping, and reduced drought tolerance. big bluestem is adapted to lean prairie soils; fertility is counterproductive for ornamental use.

Want this turned into the right next pot at the right moment? The pot size calculator and the big bluestem repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast big bluestem grows.

How to keep big bluestem smaller

You are not stuck with the maximum size. For big bluestem specifically, these are the levers, in order of impact:

Divide the clump every year or two — splitting big bluestem is the main way to control its spread and refresh it.
Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump.
Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

The keep-it-smaller method, step by step

Lift the whole plant. Slide big bluestem out of its pot in spring when the clump has filled it.
Split the clump. Tease or cut the rootball into two or more sections, each with healthy roots and growth.
Repot one division. Put a single division back in the original pot to reset it to a smaller size; pot or give away the rest.
Remove offsets as they form. Through the year, detach new runners or pups to stop it spreading again.

How to grow big bluestem bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for big bluestem the accelerators are:

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger.
Good light plus regular feeding maximises offset and runner production.
Leave plantlets and offsets attached and feed through the growing season for the fastest spread.

Light is almost always the ceiling. The big bluestem light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When big bluestem outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for big bluestem:

The clump bulging over the pot rim or splitting the pot — the cue to divide, not to find a bigger room.
A dense centre that goes bare or tired while the edges keep spreading.
Runners or offsets escaping across the shelf or into neighbouring pots.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the big bluestem repotting guide. If you want more of this plant instead of a bigger one, the big bluestem propagation guide turns prunings into new plants.

Big Bluestem size — frequently asked questions

How big does big bluestem get?

Big Bluestem reaches 120–200 cm tall in flower when grown indoors, and far larger where it grows unrestricted (clumps 60–90 cm wide). Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Is big bluestem slow or fast growing?

Big Bluestem is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Big Bluestem stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward.

How long does big bluestem take to reach full size?

Roughly three to six years to reach mature indoor size, gaining a steady amount each growing season. Light, pot size and feeding move that timeline more than anything else.

How do I keep big bluestem smaller?

Divide the clump every year or two — splitting big bluestem is the main way to control its spread and refresh it. Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump. Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

How can I make big bluestem grow bigger or faster?

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger. Good light plus regular feeding maximises offset and runner production. Leave plantlets and offsets attached and feed through the growing season for the fastest spread.