Mature size & growth rate

How big does Ribbon Grass (Phalaris arundinacea 'Picta') get?

Also called ribbon grass, gardeners garters, variegated reed canary grass.

More about ribbon grass

About Ribbon Grass

Phalaris arundinacea 'Picta' · also called ribbon grass, gardeners garters · flowering

Ribbon grass, or gardener's garters, is a cool-season variegated grass with bright white-and-green striped blades, sometimes flushed pink in cool weather. Extremely vigorous and rhizomatous, it spreads aggressively and is considered invasive in many regions, so containment is essential. Tough and adaptable, it tolerates sun or shade, wet or dry soil, making it a resilient but assertive groundcover.

Mature size: Foliage typically 60-90 cm (2-3 ft) tall, with flower stems to about 120 cm; spread is potentially unlimited by rhizomes unless contained.

Watch for — Summer browning: Foliage often browns and looks ragged in midsummer heat; shear the whole plant back hard to force fresh, clean variegated regrowth.

Indoor size vs how big it gets in the wild

Ribbon 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 typically 60-90 cm (2-3 ft) tall, with flower stems to about 120 cm. In the ground with no restriction it is a completely different plant — spread is potentially unlimited by rhizomes unless contained. — 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

Ribbon Grass is a fast grower. Realistically, expect two to four years from a young plant to a room-filling specimen in good light. Its feeding profile backs this up: needs no feeding and spreads fast enough without it; avoid fertiliser, which only accelerates its invasive rhizomatous growth. lean conditions help keep it in check.

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

How to keep ribbon grass smaller

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

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

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

When ribbon grass outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for ribbon 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 ribbon grass repotting guide. If you want more of this plant instead of a bigger one, the ribbon grass propagation guide turns prunings into new plants.

Ribbon Grass size — frequently asked questions

How big does ribbon grass get?

Ribbon Grass reaches foliage typically 60-90 cm (2-3 ft) tall, with flower stems to about 120 cm when grown indoors, and far larger where it grows unrestricted (spread is potentially unlimited by rhizomes unless contained.). 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 ribbon grass slow or fast growing?

Ribbon Grass is a fast grower. Expect two to four years from a young plant to a room-filling specimen in good light. Ribbon 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 ribbon grass take to reach full size?

Roughly two to four years from a young plant to a room-filling specimen in good light. Light, pot size and feeding move that timeline more than anything else.

How do I keep ribbon grass smaller?

Divide the clump every year or two — splitting ribbon 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 ribbon 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.