Phenological and ornamental characterization of a Geranium (Geraniaceae) germplasm collection under ex situ conditions in Central Non-Chernozem Russia

Russian State Agrarian University - Moscow Timiryazev Agricultural Academy, Moscow, 127550, Russia

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Abstract

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.