Troubleshooting
Mountain Alyssum problems — and how to fix them
Mountain Alyssum (Alyssum montanum) 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.
Legginess after flowering
Without pruning, plants become woody and open in the centre. Trim back by one-third immediately after flowering to stimulate fresh compact growth; avoid cutting hard into old wood.
Root rot from poor drainage
Sitting in wet soil, especially in winter, rapidly causes root and crown rot. Grow in raised beds, scree gardens, or slopes; top-dress with grit around the crown.
Flea beetle damage
As a Brassicaceae member, Alyssum montanum may attract flea beetles which make small shot-holes in leaves. Damage is usually cosmetic on established plants; physical barriers or sticky traps reduce infestations.
Prevent mountain alyssum problems before they start
Most mountain alyssum issues are care-mismatch, not bad luck. Dial in the basics:
Mountain Alyssum problems — FAQ
Why is my mountain alyssum legginess after flowering?
Without pruning, plants become woody and open in the centre. Trim back by one-third immediately after flowering to stimulate fresh compact growth; avoid cutting hard into old wood.
Why is my mountain alyssum root rot from poor drainage?
Sitting in wet soil, especially in winter, rapidly causes root and crown rot. Grow in raised beds, scree gardens, or slopes; top-dress with grit around the crown.
Why is my mountain alyssum flea beetle damage?
As a Brassicaceae member, Alyssum montanum may attract flea beetles which make small shot-holes in leaves. Damage is usually cosmetic on established plants; physical barriers or sticky traps reduce infestations.