SOME BIOLOGICAL FEATURES OF GERANIUM ROBERTIANUM AND G. PYRENAICUM AS HORTICULTURAL CROPS

The purpose of this work is to clarify the plants’ life expectancy and their rhythms of development, as well as the features of seed germination in geraniums of the subgenus Robertium – Geranium robertianum and G. pyrenaicum – due to the insufficient literary information about the features of their life cycles and the experience of their introduction and reproduction in Russia. G. robertianum and G. pyrenaicum are promising medicinal plants that can be used for floral decoration, because despite the small flowers, they are distinguished by a long flowering period and regular fruiting, including the ability to self-renew. The research was conducted in 2021–2023. The life forms of the studied geranium samples were clarified: G. pyrenaicum plants are rod-rooted, caudex–forming herbaceous evergreen polycarpics with semi-rosette monocarpic shoots, G. robertianum subsp. robertianum are facultative rod-rooted herbaceous evergreen biennials with semirosette monocarpic shoots. Both species bloom regularly and for a long time – from the second half of May to October with a decrease in flower productivity from the end of summer, they bear fruit in horticultural conditions of the Central NonChernozem region. The species G. pyrenaicum quickly forms a complete cover. The combined dormancy of G. robertianum seeds is shallow – six months of dry storage in heat with pre-soaking in water, which is a sufficient condition for their friendly germination. It is advisable to sow seeds in the second half of summer or autumn. Late spring or early summer sowing dates are not recommended, since in order to transit to a generative ontogenetic state, plants must undergo the necessary period with low positive temperatures at a young age. To increase the germination of G. pyrenaicum seeds after a dry storage period, it is recommended to carry out scarification or cold stratification.