Troubleshooting
Agastache 'Black Adder' problems — and how to fix them
Agastache 'Black Adder' (Agastache 'Black Adder') 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.
Winter wet rot
The main cause of loss; cold, wet soil rots the crown. Provide sharp drainage and avoid waterlogged or heavy ground.
Flopping
Stems lean in shade or over-rich soil. Site in full sun and keep soil lean for sturdy, upright growth.
Short lifespan
Can be short-lived in cool, damp climates. Take cuttings periodically to keep a supply of replacement plants.
Powdery mildew
Forms in humid, crowded plantings. Space generously, improve airflow, and water at the base rather than overhead.
Prevent agastache 'black adder' problems before they start
Most agastache 'black adder' issues are care-mismatch, not bad luck. Dial in the basics:
Looking for agastache 'black adder' in general rather than its problems? Read the full agastache 'black adder' care guide — light, water, soil and feeding.
Agastache 'Black Adder' problems — FAQ
Why is my agastache 'black adder' winter wet rot?
The main cause of loss; cold, wet soil rots the crown. Provide sharp drainage and avoid waterlogged or heavy ground.
Why is my agastache 'black adder' flopping?
Stems lean in shade or over-rich soil. Site in full sun and keep soil lean for sturdy, upright growth.
Why is my agastache 'black adder' short lifespan?
Can be short-lived in cool, damp climates. Take cuttings periodically to keep a supply of replacement plants.
Why is my agastache 'black adder' powdery mildew?
Forms in humid, crowded plantings. Space generously, improve airflow, and water at the base rather than overhead.