Do I need harsh chemicals to kill aphids?

No, insecticidal soap or even a sharp blast of water is usually enough to control them.

Will aphids kill my hydrangea?

They rarely kill a healthy plant, but they can make it look messy and weaken the new growth.

What are these bugs on my smooth hydrangea? Causes and fixes

Check these first

Look closely at the underside of new leaves.
Check for sticky honeydew on the foliage.
See if ants are traveling along the stems.

Likely causes

Aphid Infestation
Most likely
How to tell: You see clusters of tiny green or black insects on new stems and sticky residue on leaves.
What to do: Spray the plant with a strong stream of water to knock them off. If they persist, apply insecticidal soap every 5 to 7 days until they are gone.
Ant Activity
Possible
How to tell: You notice ants crawling up and down the stems of your hydrangea.
What to do: The ants are likely farming the aphids for honeydew. Treat the aphids first, and the ants will leave on their own.

Pests on other plants

Find out what's wrong with your smooth hydrangea

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

A few aphids are manageable, but a heavy infestation can stunt new growth. Treat them as soon as you spot them.

Stopping it coming back

Avoid over fertilizing with nitrogen, which creates soft growth that attracts aphids. Encourage ladybugs in your garden to eat them naturally.

Smooth Hydrangea: pests? Check yours with a photo

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

Do I need harsh chemicals to kill aphids?: No, insecticidal soap or even a sharp blast of water is usually enough to control them.
Will aphids kill my hydrangea?: They rarely kill a healthy plant, but they can make it look messy and weaken the new growth.

Guides to these causes

Aphids

What are these bugs on my smooth hydrangea?

Check these first

Not sure what's wrong with your smooth hydrangea?