Mature size & growth rate

How big does Common Quaking Grass (Briza media) get?

Also called Common quaking grass, Trembling grass, Didder grass, Rattlesnake grass.

More about common quaking grass

About Common Quaking Grass

Briza media · also called Common quaking grass, Trembling grass · flowering

A native British and European perennial meadow grass, found on old chalk grassland, limestone pastures, and unimproved neutral grassland from western Europe to central Asia. It is grown ornamentally for its distinctive heart-shaped, pendulous spikelets on hair-fine stems that tremble and rattle in the slightest breeze, opening purplish-green in late spring and drying to pale buff by midsummer. It is a cool-season grass that thrives in poor, well-drained, alkaline soils and full sun — critically, do not enrich the soil, as high fertility causes rank leafy growth and suppresses the delicate flowering display. Not listed as toxic to pets by the ASPCA; considered pet-safe.

Mature size: Foliage 20–30 cm tall; flower stems to 60–90 cm; clump spread 20–30 cm.

Watch for — Powdery mildew in warm, dry conditions: White powdery coating may appear on leaves in late summer, particularly when growth is stressed by drought or crowding; divide clumps every 3–4 years to maintain vigour and airflow.

Indoor size vs how big it gets in the wild

Common Quaking Grass 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 foliage 20–30 cm tall. In the ground with no restriction it is a completely different plant — flower stems to 60–90 cm; clump spread 20–30 cm. — 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

Common Quaking Grass 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; improved fertility suppresses the natural flowering habit. this grass thrives on neglect in poor soils.

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

How to keep common quaking grass smaller

You are not stuck with the maximum size. For common quaking grass specifically, these are the levers, in order of impact:

Divide the clump every year or two — splitting common quaking grass 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 common quaking grass 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 common quaking grass bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for common quaking grass 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 common quaking grass light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When common quaking grass outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for common quaking grass:

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 common quaking grass repotting guide. If you want more of this plant instead of a bigger one, the common quaking grass propagation guide turns prunings into new plants.

Common Quaking Grass size — frequently asked questions

How big does common quaking grass get?

Common Quaking Grass reaches foliage 20–30 cm tall when grown indoors, and far larger where it grows unrestricted (flower stems to 60–90 cm; clump spread 20–30 cm.). 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 common quaking grass slow or fast growing?

Common Quaking Grass is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Common Quaking Grass 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 common quaking grass 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 common quaking grass smaller?

Divide the clump every year or two — splitting common quaking grass 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 common quaking grass 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.