Is boxwood blight fatal?

Yes, it is a very serious disease that can kill the entire plant. Early detection and removal are the only ways to manage it.

Can I compost the fallen leaves?

Do not compost leaves that show signs of disease. Bag them up and dispose of them in the trash to prevent the spread of fungus or pests.

Why is my boxwood losing its leaves? Causes and fixes

Check these first

Look for dark spots or lesions on the fallen leaves.
Check the stems for black streaks or cankers.
Examine the leaves for small blisters or bumps.

Likely causes

Boxwood Blight
Most likely
How to tell: You will see dark brown or black spots on the leaves followed by rapid leaf drop and black streaks on the stems. This is a highly contagious fungal disease.
What to do: Remove and destroy all infected plant material immediately, being careful not to spread spores to other plants. Sanitize your pruning tools with a bleach solution after every cut.
Boxwood Leaf Miner
Possible
How to tell: The leaves develop small blisters or bumps and eventually turn yellow and drop off. If you open a blister, you might find a tiny larva inside.
What to do: Prune away heavily infested branches in early spring before the adults emerge. You can also apply a systemic insecticide labeled for leaf miners in late spring.

Leaf drop in other plants

Find out what's wrong with your common box

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.

When to worry

Worry if you see rapid defoliation and black stem lesions, as this suggests blight. A few leaves dropping in the spring is normal as the plant replaces old foliage.

Stopping it coming back

Avoid overhead watering, which keeps leaves wet and encourages fungus. Space your plants properly to ensure good air circulation.

Common box: leaf drop? Check yours with a photo

Every plant is a little different. Take a photo of your common box 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

Is boxwood blight fatal?: Yes, it is a very serious disease that can kill the entire plant. Early detection and removal are the only ways to manage it.
Can I compost the fallen leaves?: Do not compost leaves that show signs of disease. Bag them up and dispose of them in the trash to prevent the spread of fungus or pests.

Guides to these causes

Boxwood Blight

Why is my boxwood losing its leaves?