Troubleshooting
Quercus robur 'Fastigiata' problems — and how to fix them
Quercus robur 'Fastigiata' (Quercus robur 'Fastigiata') 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
Oaks, including English oak, commonly develop a white powdery mildew on late-summer growth, particularly in still, humid conditions. It is mostly cosmetic on healthy trees; avoid excess nitrogen and ensure good air movement.
Toxic acorn litter
Acorns drop in quantity in autumn and are poisonous to dogs and cats, which may chew them. Site away from pet runs and gather fallen acorns where animals have access.
Oak processionary moth (UK)
In parts of southern England this pest defoliates oaks and its hairs are an irritant to people and animals. Do not touch nests; report sightings to the relevant authority and use a professional for removal.
Galls on leaves and shoots
Various gall wasps produce knopper, marble and other galls on oaks. These look dramatic but rarely harm tree health and need no treatment.
Prevent quercus robur 'fastigiata' problems before they start
Most quercus robur 'fastigiata' issues are care-mismatch, not bad luck. Dial in the basics:
Looking for quercus robur 'fastigiata' in general rather than its problems? Read the full quercus robur 'fastigiata' care guide — light, water, soil and feeding.
Quercus robur 'Fastigiata' problems — FAQ
Why is my quercus robur 'fastigiata' powdery mildew?
Oaks, including English oak, commonly develop a white powdery mildew on late-summer growth, particularly in still, humid conditions. It is mostly cosmetic on healthy trees; avoid excess nitrogen and ensure good air movement.
Why is my quercus robur 'fastigiata' toxic acorn litter?
Acorns drop in quantity in autumn and are poisonous to dogs and cats, which may chew them. Site away from pet runs and gather fallen acorns where animals have access.
Why is my quercus robur 'fastigiata' oak processionary moth (uk)?
In parts of southern England this pest defoliates oaks and its hairs are an irritant to people and animals. Do not touch nests; report sightings to the relevant authority and use a professional for removal.
Why is my quercus robur 'fastigiata' galls on leaves and shoots?
Various gall wasps produce knopper, marble and other galls on oaks. These look dramatic but rarely harm tree health and need no treatment.