Troubleshooting
Orange King Calendula problems — and how to fix them
Orange King Calendula (Calendula officinalis 'Orange King') 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
Very common in warm, humid conditions with poor air circulation. Space plants well, water at the base, and apply potassium bicarbonate spray if needed.
Aphids
Cluster on stem tips and undersides of leaves. Blast with water or apply neem oil; ladybirds are effective biological controls.
Botrytis on spent flowers
Dead-head regularly to remove decaying petals that can harbour grey mould.
Whitefly
May appear in warm, sheltered spots. Yellow sticky traps and insecticidal soap are effective.
Ceasing to flower in heat
Blooming slows or stops above 25°C. Shear plants back by a third and they will flush again when temperatures cool.
Prevent orange king calendula problems before they start
Most orange king calendula issues are care-mismatch, not bad luck. Dial in the basics:
Orange King Calendula problems — FAQ
Why is my orange king calendula powdery mildew?
Very common in warm, humid conditions with poor air circulation. Space plants well, water at the base, and apply potassium bicarbonate spray if needed.
Why is my orange king calendula aphids?
Cluster on stem tips and undersides of leaves. Blast with water or apply neem oil; ladybirds are effective biological controls.
Why is my orange king calendula botrytis on spent flowers?
Dead-head regularly to remove decaying petals that can harbour grey mould.
Why is my orange king calendula whitefly?
May appear in warm, sheltered spots. Yellow sticky traps and insecticidal soap are effective.
Why is my orange king calendula ceasing to flower in heat?
Blooming slows or stops above 25°C. Shear plants back by a third and they will flush again when temperatures cool.