Mature size & growth rate

How big does Pheasant Tail Grass (Anemanthele lessoniana) get?

Also called pheasant tail grass, wind grass, gossamer grass.

More about pheasant tail grass

About Pheasant Tail Grass

Anemanthele lessoniana · also called pheasant tail grass, wind grass · flowering

Pheasant tail grass (Anemanthele lessoniana), a New Zealand native once classed as Stipa, is an evergreen clumping grass famed for foliage that shifts from green to fiery orange, bronze and copper as the seasons cool. In summer it throws a haze of fine, airy purplish flower panicles that catch the breeze. Drought-tolerant and graceful, it suits sunny borders, gravel gardens and containers.

Mature size: Foliage mound about 60-90 cm tall and wide; airy flower panicles arch to roughly 1-1.2 m.

Watch for — Frost damage in hard winters: Evergreen but only moderately hardy; severe cold browns or kills foliage. Mulch the crown in colder zones and comb out damaged growth in spring.

Indoor size vs how big it gets in the wild

Pheasant Tail 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 mound about 60-90 cm tall and wide. In the ground with no restriction it is a completely different plant — airy flower panicles arch to roughly 1-1.2 m. — 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

Pheasant Tail 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: light feeders. a single spring application of balanced slow-release fertiliser or a compost mulch is sufficient; excess nitrogen produces lush green growth at the expense of the prized autumn colour. on poor soils, one annual feed in spring is ample.

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

How to keep pheasant tail grass smaller

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

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

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

When pheasant tail grass outgrows the room (or the pot)

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

Pheasant Tail Grass size — frequently asked questions

How big does pheasant tail grass get?

Pheasant Tail Grass reaches foliage mound about 60-90 cm tall and wide when grown indoors, and far larger where it grows unrestricted (airy flower panicles arch to roughly 1-1.2 m.). 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 pheasant tail grass slow or fast growing?

Pheasant Tail Grass is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Pheasant Tail 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 pheasant tail 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 pheasant tail grass smaller?

Divide the clump every year or two — splitting pheasant tail 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 pheasant tail 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.