Studied seasonal development rhythms and ornamental traits of 14 Geranium species and 55 cultivars from three subgenera under ex situ conditions in Central Non-Chernozem Russia over 2021–2023. Analyzed key phenological phases including spring regrowth onset, budding, flowering, and fruiting. Established that spring regrowth occurred from mid-April to mid-May, with earlier regrowth in temperate-zone species and later in Asian-origin taxa. Identified five flowering groups based on onset: early (late May), mid-early (early June), mid-season (mid-June), mid-late (late June), and late (July). Determined that flowering duration ranged from 7 days (G. richardsonii) to 108 days (G. 'Brookside'). Evaluated floral morphology: flower diameter varied from 1, 37 cm (G. yesoense 'Nipponicum') to 5,76 cm (G. himalayense 'Derrick Cook'). Classified flower colouration into six types: solid, contrasting veins, marginal edging, longitudinal stripes, contrasting eye, and double-flowered. Identified high-performing cultivars suitable for sustainable ornamental horticulture, including G. 'Brookside', G. 'Rozanne', G. 'Patricia', and G. phaeum 'Raven', based on prolonged flowering, large flower size, and unique ornamental features.
Koryakina et al. (Thu,) studied this question.