Horticulturalization of the 21st century cities

•Rootstock-related tree alterations provide size-controlled trees for urban gardens.•Columnar, dwarf, weeping, tortuous growth forms are suitable for urban horticulture.•Disease and pest resistant/tolerant varieties expand cultivation possibilities.•Progress in biopesticide research and application foster urban gardening.•Fruit trees manage urban pollutants in ameliorative direction. Responding to the developmental challenges, as well as to the global societal and environmental urge, urban horticultural production, especially neglected fruit production can add value to the urban greenery and its ecosystem services, increasing individual gardening or community involvement, encouraging small and medium-sized allotment gardening. Albeit numerous tropical, sub-Mediterranean and ‘wild’ temperate fruit species can be applied for indoor and outdoor fruit gardening, the paper focuses on main temperate fruit species, with traditionally large canopies, grown in conventional orchards whose alterations enabled varieties and forms that completely fit urban constraints and demands. Urban gardening with analyzed species of a specific habitus or performances will allow horizontal and vertical, permanent or temporary, stationary or mobile greening, which influences climate change adaptation and mitigation, human involvement, socialization, food supply, harm reduction and environment conservation. Paper surveys numerous nature-based solutions that enable safe, successful and sustainable urban fruit production – species, selections and varieties with naturally inherited resistance/tolerance to most important disease causing agents and pests, and biopesticides that can be applied outwardly. Owing to the proposed ‘ornafruits’ urban growing, horticulturalization should contribute to re-naturing not only 21st century cities but re-naturing citizens as well. Combining presented possibilities for fruit growing expansion horticulturalization should have the problem-solving orientation towards greening the economy (increased independent healthy food production) and economizing the greenery (added value to the urban greenery), while ‘sustainability’ should finally convert from daily language expression to the daily routine of living. [Display omitted]