Troubleshooting
Liquorice Blue Korean Mint problems — and how to fix them
Liquorice Blue Korean Mint (Agastache rugosa 'Liquorice Blue') 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.
Powdery mildew
Common in humid, poorly ventilated spots. Improve air circulation, avoid overhead watering, and remove affected stems. Resistant cultivars like 'Liquorice Blue' are less susceptible but not immune.
Root rot from overwatering
Plants wilt and decline if roots sit in wet soil. Ensure sharp drainage and allow the top layer of soil to dry between waterings. Most fatal in heavy clay or compacted soil.
Flopping / legginess
Results from too much shade or overfeeding with nitrogen. Cut back by one-third after the first flush of flowers to encourage compact regrowth and a second bloom.
Prevent liquorice blue korean mint problems before they start
Most liquorice blue korean mint issues are care-mismatch, not bad luck. Dial in the basics:
Liquorice Blue Korean Mint problems — FAQ
Why is my liquorice blue korean mint powdery mildew?
Common in humid, poorly ventilated spots. Improve air circulation, avoid overhead watering, and remove affected stems. Resistant cultivars like 'Liquorice Blue' are less susceptible but not immune.
Why is my liquorice blue korean mint root rot from overwatering?
Plants wilt and decline if roots sit in wet soil. Ensure sharp drainage and allow the top layer of soil to dry between waterings. Most fatal in heavy clay or compacted soil.
Why is my liquorice blue korean mint flopping / legginess?
Results from too much shade or overfeeding with nitrogen. Cut back by one-third after the first flush of flowers to encourage compact regrowth and a second bloom.