Troubleshooting
Calendula problems — and how to fix them
Calendula (Calendula officinalis) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Powdery mildew
Most common in crowded, humid or late-season plantings; improve airflow by spacing plants and water at the base.
Aphids
Cluster on new growth and buds; calendula attracts hoverflies and parasitic wasps that help, or hose off / use insecticidal soap.
Slugs and snails
Chew young plants in damp weather; calendula is sometimes used as a trap crop to lure them off prized vegetables.
Stalls in summer heat
A cool-season plant that may stop blooming in prolonged heat, then rebounds when it cools; shear back and deadhead to refresh.
Self-seeding
Readily self-sows if spent flowers are left on the plant, returning each year; unwanted seedlings pull out easily.
Prevent calendula problems before they start
Most calendula issues are care-mismatch, not bad luck. Dial in the basics:
Calendula problems — FAQ
Why is my calendula powdery mildew?
Most common in crowded, humid or late-season plantings; improve airflow by spacing plants and water at the base.
Why is my calendula aphids?
Cluster on new growth and buds; calendula attracts hoverflies and parasitic wasps that help, or hose off / use insecticidal soap.
Why is my calendula slugs and snails?
Chew young plants in damp weather; calendula is sometimes used as a trap crop to lure them off prized vegetables.
Why is my calendula stalls in summer heat?
A cool-season plant that may stop blooming in prolonged heat, then rebounds when it cools; shear back and deadhead to refresh.
Why is my calendula self-seeding?
Readily self-sows if spent flowers are left on the plant, returning each year; unwanted seedlings pull out easily.