Troubleshooting
Thornless Boysenberry problems — and how to fix them
Thornless Boysenberry (Rubus ursinus × idaeus 'Thornless Boysenberry') 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.
Grey mould (Botrytis)
Soft, fuzzy grey rot on ripening berries in wet, crowded conditions. Improve airflow, pick fruit promptly, and remove infected berries.
Birds stripping fruit
Boysenberries are a favourite target. Net plants as fruit colours up to protect the crop.
Cane diseases (spur blight, cane blight)
Purple-brown lesions and dieback on canes. Cut out and burn affected canes after fruiting and avoid overhead watering.
Poor fruiting after hard winters
Floricanes killed by frost won't fruit. Tie canes off the cold ground and mulch the crown in zones at the cold edge of range.
Prevent thornless boysenberry problems before they start
Most thornless boysenberry issues are care-mismatch, not bad luck. Dial in the basics:
Looking for thornless boysenberry in general rather than its problems? Read the full thornless boysenberry care guide — light, water, soil and feeding.
Thornless Boysenberry problems — FAQ
Why is my thornless boysenberry grey mould (botrytis)?
Soft, fuzzy grey rot on ripening berries in wet, crowded conditions. Improve airflow, pick fruit promptly, and remove infected berries.
Why is my thornless boysenberry birds stripping fruit?
Boysenberries are a favourite target. Net plants as fruit colours up to protect the crop.
Why is my thornless boysenberry cane diseases (spur blight, cane blight)?
Purple-brown lesions and dieback on canes. Cut out and burn affected canes after fruiting and avoid overhead watering.
Why is my thornless boysenberry poor fruiting after hard winters?
Floricanes killed by frost won't fruit. Tie canes off the cold ground and mulch the crown in zones at the cold edge of range.