Selection of Garden Roses to Improve the Ecosystem Services They Provide

Abstract

With pronounced morphological and phenological diversity, garden roses have always been part of urban plantings. The significance of roses in ornamental and utilitarian (edible) horticulture can significantly be amended with novel ecosystem services, by shifting their breeding targets towards more than aesthetic and nutritional value. Thus the aim of this paper was to investigate the possibilities of newly bred (within the past decade) garden roses from the ‘Mella’ series as a possible ornamental, disease tolerant and bee attracting cultivars to be recommended in urban ecosystems, adding values to their current ecosystem services. Research goals were to determine the morphological characteristics; honey and wild bees’ abundance and its correlation with rose morphological and floral characteristics; disease resistance/tolerance to main rose fungal diseases; and suitability of ‘Mella’ roses in urban greenery providing multiple ecosystem services. Plant material included seven garden rose cultivars from the ‘Mella’ series. Analyses included complete morphological—qualitative and quantitative characterization of plant and flower traits, fragrance panel scoring and volatile components analyses, counts of honey bees visiting flowers and counts of different wild bee species as potential pollinators. Based on the obtained results significant variability in vegetative and generative plant characteristics was noted in investigated ‘Mella’ roses. With their ‘naturalistic’ overall appearance, comparable with wild roses, ‘Mella’ cultivars differed in plant height and habitus, number and type of flowers, leaf coloration and glossiness, but ‘Barbie Mella’ and ‘Ruby Mella’ positioned as the most decorative ones. ‘Barbie Mella’ was highly scored for overall fragrance, with the most divergent panel records for fragrance components and mixed volatile compounds, characterized by the balanced ratio (almost 1:1:1) between aromatic alcohol + terpenoids, straight-chain alkanes and long-chain alkanes. In relation to the honey bee’s attraction, a combination of plant height, fragrance, flower type (single, simple), flower diameter and accessibility seems to be crucial, rather than any characteristic solely. As an outstanding bee-attractor ‘Barbie Mella’ should be promoted as an ornamental disease-tolerant rose cultivar. Due to their aesthetic values, disease tolerance and bees visitations, ‘Mella’ roses ‘Barbie’, ‘Ruby’, ‘Ducat’ and ‘Exotic’ should be planted as a part of urban semi-natural gardens/landscapes, concomitantly contributing to the multiple ecosystem services—provisioning, regulating, cultural and supporting. Until their worldwide availability, other ‘Mella’-like wild and cultivated roses should be investigated and promoted likewise.