Pocket Botanist
Check these first
- Observe the amount of direct sunlight hitting the plant throughout the day.
- Inspect the inner branches to see if they are completely bare or just sparse.
- Check for any nearby structures or trees that might be casting heavy shade.
Likely causes
Insufficient Light
Most likelyHow to tell: The branches appear stretched out with large gaps between the foliage clusters. You will notice the inner parts of the tree are thinning out significantly.
What to do: Move your cedar to a location where it receives at least 6 hours of direct sun daily. If it is in a shaded spot, consider thinning nearby trees to allow more light to reach the canopy.
Improper Pruning
PossibleHow to tell: The plant looks sparse because older, woody branches were cut back too far. Thuja does not regrow foliage from old, bare wood.
What to do: Avoid cutting into the brown, woody center of the tree when trimming. Only prune the green, leafy tips to encourage a fuller shape.
Find out what's wrong with your northern white cedar
The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
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When to worry
It is serious if the inner branches are completely dead and bare, as they will not grow back. Some minor thinning in the very center is normal as the tree ages.
Stopping it coming back
Ensure your cedar gets full sun and avoid heavy pruning that cuts into the non-green wood.
Northern white cedar: leggy growth? Check yours with a photo
Every plant is a little different. Take a photo of your northern white cedar and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.
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Questions people ask
- Can I prune my Thuja to make it grow thicker?
- You can lightly trim the green tips to encourage branching, but never cut into the woody interior. Cutting into old wood will leave permanent bare spots.
- Will a leggy Thuja fill back in?
- Unfortunately, it will not fill in where the foliage has been lost on old wood. You can only encourage new growth on the current green tips.
More problems with Northern white cedar
Back to the Northern white cedar guide
This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.