Evaluation of growth and flowering of cultivars derived from the rugosa (Rosa rugosa Thunb.) growing in the national collection of rose cultivars in the Polish Academy of Sciences Botanical Garden in Powsin. Part II. The modern cultivars

In the years 2000-2011, observations were made of shrubs of the cultivars derived from the Rugosa (R. rugosa Thunb.) gathered in the Collection of Rose Cultivars of the Polish Academy of Sciences (PAS) Botanical Garden - Center for Biological Diversity Conservation (CBDC) in Powsin, Poland, including 29 varieties. In the second part, the results are presented for 17 modern cultivars (‘Bokratrack’, ‘Dart’s Defender’, ‘Handwar’, ‘Hanpur’, ‘Hansno’, ‘Hanuhl’, ‘Korgosa’, ‘Korhassi’, ‘Korruge’, ‘Magsed’, ‘Rokoko’, ‘Speruge’, ‘Strolen’, ‘Stronin’, ‘Thérèse Bugnet’, ‘Uhlwe’, ‘White Grootendorst’). Every year, damage to shrubs caused by frost was recorded; the date of bud break and the date when leaves developed in springtime were recorded; regeneration of shrubs damaged in winter was observed; the dates of initial, full and final flowering were recorded; the presence of disease symptoms was observed; and notes were made concerning the need to do spring pruning and pruning after flowering. The winter seasons 2002/2003, 2005/2006, 2009/2010, 2010/2011 were unfavourable for roses. In terms of the features in question, the cultivars varied. The observations made confirm the high frost resistance of Rugosa hybrids and their low cultivation requirements, owing to which they deserve a wider application, in accordance with their intended use, both as amateur varieties and for urban green areas.