Troubleshooting
Coral Bells 'Obsidian' problems — and how to fix them
Coral Bells 'Obsidian' (Heuchera 'Obsidian') 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 rot
The primary cause of Heuchera failure; ensure the crown sits slightly above soil level and drainage is excellent.
Vine weevil
Look for U-shaped notches on leaf margins; apply nematode treatment in late summer to combat larvae at the roots.
Foliar nematodes
Brown wedge-shaped lesions bounded by leaf veins; remove affected foliage and avoid overhead irrigation.
Leaf colour fade
Dark pigmentation fades to green-brown in deep shade or with excess nitrogen feeding; ensure some indirect light and a low-nitrogen fertiliser.
Powdery mildew
Pale coating on leaves during dry spells; water consistently and improve air circulation.
Prevent coral bells 'obsidian' problems before they start
Most coral bells 'obsidian' issues are care-mismatch, not bad luck. Dial in the basics:
Coral Bells 'Obsidian' problems — FAQ
Why is my coral bells 'obsidian' crown rot?
The primary cause of Heuchera failure; ensure the crown sits slightly above soil level and drainage is excellent.
Why is my coral bells 'obsidian' vine weevil?
Look for U-shaped notches on leaf margins; apply nematode treatment in late summer to combat larvae at the roots.
Why is my coral bells 'obsidian' foliar nematodes?
Brown wedge-shaped lesions bounded by leaf veins; remove affected foliage and avoid overhead irrigation.
Why is my coral bells 'obsidian' leaf colour fade?
Dark pigmentation fades to green-brown in deep shade or with excess nitrogen feeding; ensure some indirect light and a low-nitrogen fertiliser.
Why is my coral bells 'obsidian' powdery mildew?
Pale coating on leaves during dry spells; water consistently and improve air circulation.