Pocket BotanistCheck these first
- Look closely for small silk bags hanging from the branches.
- Shake a branch over a white paper to see if any insects fall off.
- Check the soil moisture to see if the tree is severely dehydrated.
Likely causes
Bagworms
Most likelyHow to tell: You will see small, cone-shaped bags made of silk and foliage hanging from the branches. These caterpillars eat the leaves, causing them to fall off and leaving bare patches.
What to do: Pick the bags off by hand and drop them into a bucket of soapy water. If the infestation is widespread, use a biological insecticide like Bt during the caterpillar's active phase.
Severe drought
PossibleHow to tell: The foliage turns brown and drops off in large quantities during extended dry periods. The tree is shedding leaves to conserve its remaining water.
What to do: Increase your watering frequency to ensure the root zone stays hydrated. Apply a thick layer of mulch to keep the soil cool and moist.
Find out what's wrong with your arborvitae
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 normal for Arborvitae to shed some interior needles in the fall. Worry if you see significant thinning or bare branches on the outer canopy.
Stopping it coming back
Monitor your tree regularly for pests and provide supplemental water during hot, dry summer months.
Keep your arborvitae healthy from here
Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked. Identification and a health check are free.
Questions people ask
- Will the leaves grow back on bare branches?
- Arborvitae generally do not grow new foliage on old, woody branches. The tree will only grow outward from the current green tips.
- Are bagworms hard to get rid of?
- They are manageable if caught early. Hand-picking is very effective for small trees.
More problems with Arborvitae
This article was generated with AI from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.