Troubleshooting
Oleander problems — and how to fix them
Oleander (Nerium oleander) 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.
Oleander scale
Armoured scale insects cluster on leaves and stems, weakening the plant and fostering sooty mould. Treat with horticultural oil and prune out heavily infested wood.
Sooty mould
Black coating from honeydew left by scale or aphids. Cosmetic but blocks light; control the sap-suckers and the mould fades.
Root rot from overwatering
Yellowing leaves and dieback in soggy soil. Improve drainage and let the soil dry between waterings; oleander far prefers dry to wet feet.
Frost damage
Stems and foliage are scorched below about -5°C. Mulch the crown, grow in a sheltered spot, or move containers under cover for winter in cold regions.
Prevent oleander problems before they start
Most oleander issues are care-mismatch, not bad luck. Dial in the basics:
Looking for oleander in general rather than its problems? Read the full oleander care guide — light, water, soil and feeding.
Oleander problems — FAQ
Why is my oleander oleander scale?
Armoured scale insects cluster on leaves and stems, weakening the plant and fostering sooty mould. Treat with horticultural oil and prune out heavily infested wood.
Why is my oleander sooty mould?
Black coating from honeydew left by scale or aphids. Cosmetic but blocks light; control the sap-suckers and the mould fades.
Why is my oleander root rot from overwatering?
Yellowing leaves and dieback in soggy soil. Improve drainage and let the soil dry between waterings; oleander far prefers dry to wet feet.
Why is my oleander frost damage?
Stems and foliage are scorched below about -5°C. Mulch the crown, grow in a sheltered spot, or move containers under cover for winter in cold regions.