Troubleshooting
Heuchera 'Mahogany' problems — and how to fix them
Heuchera 'Mahogany' (Heuchera 'Mahogany') 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
Excessive moisture at the crown causes rapid rotting; excellent drainage and correct planting depth are the primary prevention.
Vine weevil
Crescent-shaped leaf notches indicate adults; pale grubs in the root zone are the more damaging larval stage — apply nematodes in late summer.
Botrytis grey mould
Fuzzy grey mould on stems and leaves in cold, wet conditions; improve airflow, remove affected material, and allow the soil surface to dry between waterings.
Rust fungus
Orange spore pustules on leaf undersides in humid weather; remove affected leaves and treat with a copper fungicide at first appearance.
Leaf scorch
Brown crispy leaf edges in hot or exposed sites; move to a shadier, more sheltered position and maintain adequate soil moisture.
Prevent heuchera 'mahogany' problems before they start
Most heuchera 'mahogany' issues are care-mismatch, not bad luck. Dial in the basics:
Heuchera 'Mahogany' problems — FAQ
Why is my heuchera 'mahogany' crown rot?
Excessive moisture at the crown causes rapid rotting; excellent drainage and correct planting depth are the primary prevention.
Why is my heuchera 'mahogany' vine weevil?
Crescent-shaped leaf notches indicate adults; pale grubs in the root zone are the more damaging larval stage — apply nematodes in late summer.
Why is my heuchera 'mahogany' botrytis grey mould?
Fuzzy grey mould on stems and leaves in cold, wet conditions; improve airflow, remove affected material, and allow the soil surface to dry between waterings.
Why is my heuchera 'mahogany' rust fungus?
Orange spore pustules on leaf undersides in humid weather; remove affected leaves and treat with a copper fungicide at first appearance.
Why is my heuchera 'mahogany' leaf scorch?
Brown crispy leaf edges in hot or exposed sites; move to a shadier, more sheltered position and maintain adequate soil moisture.