Pocket Botanist
Check these first
- Inspect the undersides of the leaves for orange dust.
- Check if the spots have a yellow halo around them.
- Look for nearby grasses that might also show signs of rust.
Likely causes
Crown Rust Fungus
Most likelyHow to tell: You will see bright orange, powdery spots on the undersides of leaves. These spots often appear in late spring or early summer.
What to do: Prune away heavily infected branches to improve airflow. Clean your pruning shears with rubbing alcohol after each cut to avoid spreading spores. Avoid overhead watering to keep the foliage as dry as possible.
Leaf Spot Disease
PossibleHow to tell: These spots are usually brown or black with a yellow halo. They appear randomly across the leaf surface rather than in clusters.
What to do: Rake up and dispose of all fallen leaves beneath the shrub to remove overwintering spores. Apply a copper based fungicide if the infection is severe, following the label instructions for dosage.
Find out what's wrong with your common buckthorn
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.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
When to worry
It is rarely fatal for a mature buckthorn, but it can look unsightly. Worry if the entire shrub is covered and losing leaves prematurely.
Stopping it coming back
Keep the area around the base of the plant clear of debris and ensure good air circulation by pruning crowded branches.
Common buckthorn: spots? Check yours with a photo
Every plant is a little different. Take a photo of your common buckthorn 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.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
Get the app · Or check it from a photo now, free
Questions people ask
- Will this kill my buckthorn?
- No, crown rust is generally not fatal to common buckthorn. It mostly just affects the appearance of the foliage.
- Can I compost the infected leaves?
- It is best to bag and trash them. Home compost piles often do not get hot enough to kill fungal spores.
Guides to these causes
More problems with Common buckthorn
- Why are my Common buckthorn leaves turning yellow?
- Why are the tips of my Common buckthorn leaves turning brown?
- Why is my common buckthorn drooping?
- Why is my common buckthorn losing its leaves?
- What is eating my common buckthorn?
- Why is my common buckthorn showing signs of root rot?
- Why is my common buckthorn growing so leggy?
Back to the Common buckthorn 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.