Are these spots contagious to my other plants?

Most fungal leaf spots are specific to the sumac family and will not spread to your garden vegetables or flowers. However, it is always best to clean up fallen leaves to keep the area tidy.

Should I spray the tree with fungicide?

Usually, no. Smooth sumacs are tough plants that can handle minor leaf spots without chemical intervention.

Smooth sumac: spots, causes and fixes

Check these first

Inspect the spots to see if they are flat or raised galls.
Look for fungal growth or webbing on the undersides of leaves.
Check if the spots are spreading rapidly after a rainy spell.

Likely causes

Fungal leaf spot
Possible
How to tell: You will see small brown or black circular spots that may have a yellow halo around them. These spots often appear after periods of high humidity or heavy rain.
What to do: Prune away the most heavily affected branches to improve airflow through the canopy. Clean up and dispose of any fallen leaves beneath the plant to prevent spores from overwintering. Avoid overhead watering to keep the foliage dry.
Sumac gall aphid
Possible
How to tell: These look like odd, bumpy growths or galls on the leaves rather than flat spots. They are caused by tiny aphids and are generally harmless to the overall health of the tree.
What to do: Simply leave them alone as they do not harm the tree. If you dislike the look, you can prune off the affected leaflets. Avoid using heavy pesticides as these often kill beneficial insects that manage the aphid population.

Leaf spots on other plants

Find out what's wrong with your smooth sumac

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 the spots are accompanied by significant leaf drop or branch dieback. It is normal for a few older leaves to develop minor blemishes as the season progresses.

Stopping it coming back

Keep the area around the base of your sumac clear of debris and ensure it has plenty of space for air to circulate.

Smooth sumac: spots? Check yours with a photo

Every plant is a little different. Take a photo of your smooth sumac 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.

Get the app · Or check it from a photo now, free

Questions people ask

Are these spots contagious to my other plants?: Most fungal leaf spots are specific to the sumac family and will not spread to your garden vegetables or flowers. However, it is always best to clean up fallen leaves to keep the area tidy.
Should I spray the tree with fungicide?: Usually, no. Smooth sumacs are tough plants that can handle minor leaf spots without chemical intervention.

Guides to these causes

Leaf Spot

Why does my smooth sumac have spots on its leaves?