Mature size & growth rate

How big does Silvery Yarrow (Achillea clavennae) get?

Also called Silvery Yarrow, Clavenna's Yarrow, White Yarrow.

More about silvery yarrow

About Silvery Yarrow

Achillea clavennae · also called Silvery Yarrow, Clavenna's Yarrow · flowering

Achillea clavennae is a low-growing alpine yarrow from the limestone mountains of central and southern Europe, forming silvery-white, finely dissected foliage mats topped with small white daisy-like flowerheads from early to midsummer. Extremely drought and heat tolerant once established, it is ideal for dry rock gardens, gravel gardens, and sunny alpine troughs.

Mature size: 15–25 cm tall in flower, 30–45 cm wide

Indoor size vs how big it gets in the wild

Silvery Yarrow 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 15–25 cm tall in flower, 30–45 cm wide. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

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

Silvery Yarrow 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: little to no feeding required. achillea clavennae grows naturally in nutrient-poor limestone soils. an annual topdress of grit around the plant is more beneficial than fertiliser. if growth appears very weak, a single application of a low-nitrogen slow-release granular feed in spring is sufficient.

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

How to keep silvery yarrow smaller

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

Divide the clump every year or two — splitting silvery yarrow 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 silvery yarrow 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 silvery yarrow bigger or faster

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

When silvery yarrow outgrows the room (or the pot)

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

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

Silvery Yarrow size — frequently asked questions

How big does silvery yarrow get?

Silvery Yarrow reaches 15–25 cm tall in flower, 30–45 cm wide when grown indoors. 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 silvery yarrow slow or fast growing?

Silvery Yarrow is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Silvery Yarrow 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 silvery yarrow 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 silvery yarrow smaller?

Divide the clump every year or two — splitting silvery yarrow 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 silvery yarrow 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.