Mature size & growth rate

How big does Sichuan Arborvitae (Thuja sutchuenensis) get?

Also called Sichuan White Cedar, Chinese Arborvitae.

More about sichuan arborvitae

About Sichuan Arborvitae

Thuja sutchuenensis · also called Sichuan White Cedar, Chinese Arborvitae · flowering

Sichuan Arborvitae is a critically endangered conifer from China's Daba Mountains, prized for its flat, scale-like foliage and neat conical form. It thrives in cool, well-drained sites with consistent moisture and tolerates moderate frost. Not individually listed by the ASPCA; the Thuja genus contains thujone and should be kept away from pets.

Mature size: 3-8 m tall in garden conditions; slow-growing

Indoor size vs how big it gets in the wild

Sichuan Arborvitae is a tree at heart. Indoors a pot and your ceiling keep it to 3-8 m tall in garden conditions, but in the ground it is a different scale of plant entirely (slow-growing). Indoors and in a pot, expect 3-8 m tall in garden conditions. In the ground with no restriction it is a completely different plant — slow-growing — which is why the pot, the light and the pruning matter so much for the size you actually end up with.

It gains real height on a trunk or main stem, adding a tier of leaves a year and eventually reaching for the ceiling — this is a plant you grow up, not out.

Growth rate and years to mature

Sichuan Arborvitae is a slow grower. Realistically, expect a decade or more — slow growers like this add only a few centimetres a year, so expect 8-15+ years to reach their indoor ceiling. Its feeding profile backs this up: apply a balanced slow-release fertiliser (e.g., 10-10-10) once in early spring as new growth begins. avoid over-fertilising, which can cause weak, lush growth vulnerable to pest damage.

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

How to keep sichuan arborvitae smaller

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

The decisive tool is the secateurs: sichuan arborvitae can be topped (cut the main growing tip) to cap its height and force a bushier, shorter shape.
Keeping it deliberately pot-bound in a snug container slows the whole plant and limits ultimate size.
Prune in spring so it heals fast; remove the tallest leader back to a node to reset the height.
Good news: slow growth means topping it once buys you years before it needs doing again.

The keep-it-smaller method, step by step

Pick the new height. Decide how tall you want sichuan arborvitae and find a leaf node or branch point just below that.
Top the main stem. Cut the main growing tip cleanly just above that node in spring; this permanently caps the height and forces side branches.
Keep the pot snug. Avoid jumping to a much bigger pot — a slightly restricted rootball keeps the whole plant smaller.
Maintain the shape. Prune back the tallest new leaders each spring to hold it at the height you chose.

How to grow sichuan arborvitae bigger or faster

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

It already wants the bright light it needs; warmth, a yearly pot-up and spring-summer feed are the accelerators.
Pot up a size every year or two while young; restricted roots are the main thing holding height back.
Feed regularly through the growing season and keep it warm — height comes from sustained good conditions.

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

When sichuan arborvitae outgrows the room (or the pot)

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

The top leaves pressing against or bent by the ceiling — the classic "this is now too tall indoors" sign.
It has to be moved away from a light source it has literally outgrown.
Roots filling the largest pot you can reasonably keep indoors — at that point it is top-or-prune or move it outside (if hardy).

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

Sichuan Arborvitae size — frequently asked questions

How big does sichuan arborvitae get?

Sichuan Arborvitae reaches 3-8 m tall in garden conditions when grown indoors, and far larger where it grows unrestricted (slow-growing). It gains real height on a trunk or main stem, adding a tier of leaves a year and eventually reaching for the ceiling — this is a plant you grow up, not out.

Is sichuan arborvitae slow or fast growing?

Sichuan Arborvitae is a slow grower. Expect a decade or more — slow growers like this add only a few centimetres a year, so expect 8-15+ years to reach their indoor ceiling. Sichuan Arborvitae is a tree at heart. Indoors a pot and your ceiling keep it to 3-8 m tall in garden conditions, but in the ground it is a different scale of plant entirely (slow-growing).

How long does sichuan arborvitae take to reach full size?

Roughly a decade or more — slow growers like this add only a few centimetres a year, so expect 8-15+ years to reach their indoor ceiling. Light, pot size and feeding move that timeline more than anything else.

How do I keep sichuan arborvitae smaller?

The decisive tool is the secateurs: sichuan arborvitae can be topped (cut the main growing tip) to cap its height and force a bushier, shorter shape. Keeping it deliberately pot-bound in a snug container slows the whole plant and limits ultimate size. Prune in spring so it heals fast; remove the tallest leader back to a node to reset the height. Good news: slow growth means topping it once buys you years before it needs doing again.

How can I make sichuan arborvitae grow bigger or faster?

It already wants the bright light it needs; warmth, a yearly pot-up and spring-summer feed are the accelerators. Pot up a size every year or two while young; restricted roots are the main thing holding height back. Feed regularly through the growing season and keep it warm — height comes from sustained good conditions.