Nice photos, Horst, thank you. Morden Ruby is bred from R. Arkansana, an American species rose. Arkansana is deciduous and Morden Ruby has inherited a good dose of the deciduous character. Once the plant is triggered by climate, it begins shedding its foliage for the winter in an effort to harden off and become more cold hardy. I experienced this with it when I grew it in the mid desert here in Southern California. It's unfortunate that in warmer climates, this going deciduous is often accompanied by rust infections. Otherwise, it is a very unusual, interesting rose.