Troubleshooting
Jean's Dilly Spruce problems — and how to fix them
Jean's Dilly Spruce (Picea glauca 'Jean's Dilly') is generally low-drama, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Red spider mite (Oligonychus ununguis)
The most serious and common pest of this cultivar; infestations appear as bronzing, stippling, and needle loss, typically in hot, dry weather from June onwards. Spray foliage with a strong jet of water weekly to dislodge mites, maintain soil moisture, and apply a miticide if infestations are severe; vigilance is needed every summer.
Cytospora canker (Cytospora kunzei)
Fungal canker causing resin-soaked dead patches on branches, typically entering through wounds or stress points; infected branches die from the tip back. Prune out infected material with sterile tools during dry weather and avoid wounding the bark; maintain good plant vigour through adequate watering.
Prevent jean's dilly spruce problems before they start
Most jean's dilly spruce issues are care-mismatch, not bad luck. Dial in the basics:
Jean's Dilly Spruce problems — FAQ
Why is my jean's dilly spruce red spider mite (oligonychus ununguis)?
The most serious and common pest of this cultivar; infestations appear as bronzing, stippling, and needle loss, typically in hot, dry weather from June onwards. Spray foliage with a strong jet of water weekly to dislodge mites, maintain soil moisture, and apply a miticide if infestations are severe; vigilance is needed every summer.
Why is my jean's dilly spruce cytospora canker (cytospora kunzei)?
Fungal canker causing resin-soaked dead patches on branches, typically entering through wounds or stress points; infected branches die from the tip back. Prune out infected material with sterile tools during dry weather and avoid wounding the bark; maintain good plant vigour through adequate watering.