Rubus × 'John Innes' is a historic, late-fruiting thornless blackberry cultivar that emerged from the John Innes Horticultural Institution in the UK during the early 20th century. It was developed through a deliberate cross between the European wild blackberry species Rubus ulmifolius var. inermis and the tetraploid Rubus hastiformis. The breeding objective was to transfer the rare, naturally occurring "inermis" (thornless) mutation from R. ulmifolius into a more vigorous, high-yielding genetic background. This hybridization was a scientific milestone, as it required overcoming ploidy differences to produce a fertile, thornless offspring that paved the way for modern bramble genetics.

The fruit of 'John Innes' is medium-sized, exceptionally juicy, and noted for a rich, "wild" blackberry flavor that is often lost in larger, more modern commercial hybrids. It has a trailing growth habit, inherited from its wild European ancestors, which necessitates a robust trellis system for cultivation. Because it ripens much later than most other cultivars—often extending the harvest into late September—it occupies a unique niche in the seasonal culinary calendar. It also contains high levels of tannins which contribute to the slightly astringent finish characteristic of traditional European brambles, making it a favorite for artisanal syrups and fermented cordials.