Mature size & growth rate

How big does Hiba Arborvitae (Thujopsis dolabrata) get?

Also called Hiba Arborvitae, Deerhorn Cedar, False Arborvitae, Hiba.

More about hiba arborvitae

About Hiba Arborvitae

Thujopsis dolabrata · also called Hiba Arborvitae, Deerhorn Cedar · flowering

Hiba Arborvitae is a striking Japanese conifer producing large, flattened foliage sprays of bold, glossy deep-green scales with distinctive bright silvery-white markings underneath. Native to cool, moist montane forests of Japan, it demands consistently moist, well-drained soil and dislikes drought or dry air. Handsome as a specimen or informal screen and fully hardy in temperate gardens.

Mature size: 15–30 m tall in habitat; typically 8–15 m tall by 3–6 m wide in UK/European cultivation; var. hondae stays smaller

Indoor size vs how big it gets in the wild

Hiba Arborvitae is a tree at heart. Indoors a pot and your ceiling keep it to 15–30 m tall in habitat, but in the ground it is a different scale of plant entirely (typically 8–15 m tall by 3–6 m wide in uk/european cultivation; var. hondae stays smaller). Indoors and in a pot, expect 15–30 m tall in habitat. In the ground with no restriction it is a completely different plant — typically 8–15 m tall by 3–6 m wide in uk/european cultivation; var. hondae stays smaller — 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

Hiba 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 balanced slow-release fertiliser in early spring. a light top-dressing of leaf mould or composted bark in autumn supports soil moisture retention and feeds the roots gently. avoid excessive feeding, which produces soft, disease-prone growth.

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

How to keep hiba arborvitae smaller

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

The decisive tool is the secateurs: hiba 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 hiba 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 hiba arborvitae bigger or faster

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

When hiba arborvitae outgrows the room (or the pot)

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

Hiba Arborvitae size — frequently asked questions

How big does hiba arborvitae get?

Hiba Arborvitae reaches 15–30 m tall in habitat when grown indoors, and far larger where it grows unrestricted (typically 8–15 m tall by 3–6 m wide in uk/european cultivation; var. hondae stays smaller). 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 hiba arborvitae slow or fast growing?

Hiba Arborvitae is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Hiba Arborvitae is a tree at heart. Indoors a pot and your ceiling keep it to 15–30 m tall in habitat, but in the ground it is a different scale of plant entirely (typically 8–15 m tall by 3–6 m wide in uk/european cultivation; var. hondae stays smaller).

How long does hiba 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 hiba arborvitae smaller?

The decisive tool is the secateurs: hiba 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 hiba 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.