Troubleshooting
Free-flowering Streptocarpus problems — and how to fix them
Free-flowering Streptocarpus (Streptocarpus floribundus) 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.
Crown and root rot
The most frequent killer; caused by wet, compacted compost or water sitting in the crown. Repot into fresh open mix, remove all soft or blackened tissue, and dust cut surfaces with cinnamon or powdered sulphur before repotting.
Powdery mildew
White powdery coating on leaf surfaces occurs in stagnant, humid air with low light; improve ventilation, remove affected leaves, and apply a potassium bicarbonate or sulphur-based fungicide.
Vine weevil larvae
C-shaped grubs eat roots, causing sudden wilt; unpot to inspect and treat with biological controls (Steinernema kraussei nematodes applied in autumn) or a licensed vine weevil compost drench.
Prevent free-flowering streptocarpus problems before they start
Most free-flowering streptocarpus issues are care-mismatch, not bad luck. Dial in the basics:
Free-flowering Streptocarpus problems — FAQ
Why is my free-flowering streptocarpus crown and root rot?
The most frequent killer; caused by wet, compacted compost or water sitting in the crown. Repot into fresh open mix, remove all soft or blackened tissue, and dust cut surfaces with cinnamon or powdered sulphur before repotting.
Why is my free-flowering streptocarpus powdery mildew?
White powdery coating on leaf surfaces occurs in stagnant, humid air with low light; improve ventilation, remove affected leaves, and apply a potassium bicarbonate or sulphur-based fungicide.
Why is my free-flowering streptocarpus vine weevil larvae?
C-shaped grubs eat roots, causing sudden wilt; unpot to inspect and treat with biological controls (Steinernema kraussei nematodes applied in autumn) or a licensed vine weevil compost drench.