Thuja - planting, pruning and advice on caring for this excellent hedge tree

Backlit branch of thuja against a black background

Thuja isn’t the most elegant conifer, nor is it a hedge shrub that is particularly supportive of biodiversity, but it does, however, excel in cutting off the view for intrusive onlookers.

Key facts about thuja

Name – Thuja
Often misspelled as – Thuya
Family – Cupressaceae

Type – conifer
Height – up to 65 feet (20 meters)
Exposure – full sun to shade

Soil – ordinary, well drained
Foliage – evergreen

A very fast grower, it is one of the most commonly used species to set up hedges.

Planting thuja

Thuja is a conifer usually planted as part of a hedge, and is often set up at the beginning of fall, but it can also be planted until March or April as long as it doesn’t freeze.

When purchased in containers, a thuja can be planted in the ground almost all year round, except when it freezes.

Thuja loves full sun exposure or part shade.
The thuja shrub copes well with any type of soil.

After planting, you can also mulch the foot of the tree in order to avoid having weeds crowd it out from below but also to protect the roots from the cold.

In both cases, maritime pine bark mulch is the most perfectly suited, but any other mulch will also play the part fine.

Pruning thuja shrubs and thuja hedges

If your thuja is never pruned, it can grow to reach nearly 65 feet (20 meters) and its bearing will be a distinctive cone.
For hedges, select the pruning height you are comfortable with as well as the thickness.

Prune your thuja preferably at the end of summer or at the beginning of spring.
Feel free to prune severely because thuja tends to grow very, very fast.

A heavy pruning end of August is enough to keep this growth under control.
That is also the season where sap descends and so it will slow the thuja’s growth a bit.

Spring pruning is usually with rising sap and tends to accelerate the tree’s growth, so this is ideal if you aim to hide yourself from prying neighbor’s view.

Watch out then for the growth of this conifer if you’ve got neighbors nearby, because it might lead to problems.
See also our pruning tips for hedges

Diseases and parasites that attack thuja

Thuja is very disease-resistant and resists fungus, too.

Although it’s rare, an occurrence of fire blight can wipe a complete hedge out in only a few days.
Branches turn brown and die and this can lead to the death of the entire tree.
Be careful! This disease can lead to the entire hedge dying off.
In even rarer cases, a bout of rust or scale insects will appear.

Learn more about thuja

The thuja tree is native to North America, where it’s commonly called Arborvitae, which means “tree of life” in Latin. This name was given it for its evergreen foliage that stays put from January to December.

It’s also reputed to be an excellent wind-breaker, ready to resist gales of any power – and block out inquisitive neighbors, too; this particular trait is what makes it an extremely common choice for setting a hedge up.

They are also very resilient in the face of disease and pollution.

From an aesthetic point of view, it doesn’t have any other advantage than the deep green that lasts all year round and a high opaqueness.

Also, know that if the climate is hot in summer, thuja might not be your best candidate because it requires water.

Smart tip about thuja

When part of a hedge, think well about how high you want it to grow so that you can determine the planting distance of your thuja accordingly! Keep a spacing of about 32 inches (80 cm) to 3 feet (1 meter) for the usual 6-foot (1.80 m) hedge.