Mature size & growth rate

How big does Oriental Arborvitae (Platycladus orientalis) get?

Also called Oriental Arborvitae, Chinese Arborvitae, Asian Arborvitae, Oriental Thuja.

More about oriental arborvitae

About Oriental Arborvitae

Platycladus orientalis · also called Oriental Arborvitae, Chinese Arborvitae · flowering

Oriental Arborvitae is a dense, evergreen conifer from northern China, valued for its vertical foliage sprays held in upright flattened planes — a key distinguishing feature from Western arborvitaes. It thrives in full sun, tolerates drought and alkaline soils, and suits hot, dry climates where other conifers struggle. Widely used in formal hedging and specimen planting.

Mature size: 5.5–8 m tall by 2–4 m wide in cultivation; can reach 10–15 m in ideal conditions

Indoor size vs how big it gets in the wild

Oriental Arborvitae is a tree at heart. Indoors a pot and your ceiling keep it to 5.5–8 m tall by 2–4 m wide in cultivation, but in the ground it is a different scale of plant entirely (can reach 10–15 m in ideal conditions). Indoors and in a pot, expect 5.5–8 m tall by 2–4 m wide in cultivation. In the ground with no restriction it is a completely different plant — can reach 10–15 m in ideal conditions — 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

Oriental Arborvitae 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: apply a slow-release balanced granular fertiliser in early spring. a single annual application is generally sufficient for established trees. young plants benefit from a dilute balanced liquid feed monthly during the growing season to accelerate establishment.

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

How to keep oriental arborvitae smaller

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

The decisive tool is the secateurs: oriental 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.
Expect to top or hard-prune it every year or two — left alone it heads for the ceiling.

The keep-it-smaller method, step by step

Pick the new height. Decide how tall you want oriental 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 oriental arborvitae bigger or faster

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

When oriental arborvitae outgrows the room (or the pot)

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

Oriental Arborvitae size — frequently asked questions

How big does oriental arborvitae get?

Oriental Arborvitae reaches 5.5–8 m tall by 2–4 m wide in cultivation when grown indoors, and far larger where it grows unrestricted (can reach 10–15 m in ideal conditions). 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 oriental arborvitae slow or fast growing?

Oriental Arborvitae is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Oriental Arborvitae is a tree at heart. Indoors a pot and your ceiling keep it to 5.5–8 m tall by 2–4 m wide in cultivation, but in the ground it is a different scale of plant entirely (can reach 10–15 m in ideal conditions).

How long does oriental arborvitae 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 oriental arborvitae smaller?

The decisive tool is the secateurs: oriental 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. Expect to top or hard-prune it every year or two — left alone it heads for the ceiling.

How can I make oriental 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.