Will aphids kill my sowthistle?

Usually no, but they can weaken the plant significantly. They suck the sap, which stunts growth and can spread viruses.

Yes, neem oil is effective against aphids. Apply it in the evening to avoid harming bees and other pollinators.

Perennial sowthistle: pests, causes and fixes

Check these first

Inspect the undersides of leaves for clusters of small insects.
Look for sticky residue on the stems or foliage.
Check if the plant is receiving at least 6 to 8 hours of direct sun.

Likely causes

Aphid infestation
Most likely
How to tell: You will see small green or black insects huddled together on stems and leaf undersides. They often leave behind a sticky substance called honeydew.
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.
Environmental stress
Possible
How to tell: Plants that are struggling from lack of sun or water are more prone to pest attacks. The plant may look generally weak or stunted.
What to do: Ensure your sowthistle is in a spot with full sun. Adjust your watering schedule to keep the soil consistently moist but not soggy.

Pests on other plants

Find out what's wrong with your perennial sowthistle

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

Small numbers of aphids are normal in a garden, but you should act if they start causing leaf curling or stunted growth. If the plant is covered in pests and looks severely wilted, it may be too late to save.

Stopping it coming back

Keep your plant healthy with proper sun and water to help it resist infestations. You can also encourage beneficial insects like ladybugs to visit your garden.

Perennial sowthistle: pests? Check yours with a photo

Every plant is a little different. Take a photo of your perennial sowthistle 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

Will aphids kill my sowthistle?: Usually no, but they can weaken the plant significantly. They suck the sap, which stunts growth and can spread viruses.
Can I use neem oil?: Yes, neem oil is effective against aphids. Apply it in the evening to avoid harming bees and other pollinators.

Guides to these causes

Aphids

Why are there bugs on my perennial sowthistle?

Check these first

Not sure what's wrong with your perennial sowthistle?