I have been growing this plant for a few years now on a north east facing windowsill. It grows and flowers beautifully, but it doesn't shed its leaves until a couple of weeks before the new shoots start forming in the spring, instead of shedding them in the autumn. I thought this might be environmental so one year I grew a division of the plant under the staging in my cool greenhouse, however it still hung onto its leaves all winter! Is this unusual? I must admit it is rather inconveniently large in the winter when my windowsill is packed with orchids that spend summer in the garden and greenhouse.