Why has my thornless blackberry become thorny?

Thornless blackberries are a blessing – cut-free hands and masses of berries ripe for picking. Surprisingly, thorns can appear, though. If this is true for your thornless blackberry plant, watch this video. Kate Bradbury, BBC Gardeners' World Magazine explains why thorny growth may appear, and gives her tips on how to tackle it if spotted.

Looking to grow thornless blackberries? Take a look at two thornless cultivars, 'Adrienne' and 'Loch Ness'.