This report covers the conspicuous trend of increase of garden flowers that could not survive severe winter over their bearable low temperature before. This trend may be occurred through one or two factors of so-called global warming and urban heat island （UHI） in this area near the centre of one of Japanʼs largest cities. （Fig.1） From the winter starting Dec. 1986 to the next early spring of 1987, coldness of winter declined dramatically as shown in Figures 3 to 4 and the table 1. The reporter has no data of UHI, so could not judge which one of the two factors may work mainly or cause warm winters in this area. Garden flowers that were introduced from the warmer district or countries hate low temperatures, so they should have been cultivated only in green houses before these warm winters. The report may show some quasi-tropical plants winter outdoors without any protectional anti-cold device in the middle part of Yokohama. This report might elaborate some astonishing sessile witnesses of these warming winters.
Key words: quasi-tropical plants, winter outdoors, sessile witnesses, warm winters, yokohama

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