The fourth species of Galanthus we grow in our garden is woronowii, the Caucasian snowdrop, from the Transcaucasus down into Turkey. It is distinct in its bright green foliage, and tolerates drier conditions than nivalis, the common snowdrop. It also spreads rapidly; from a few bulbs two years ago I now have quite a good sized patch... it is said that it needs to be divided every three years to maximize flowering, as it rapidly becomes congested. I will not consider this to be an undue burden. The only negative is that it does have a propensity to have its open foliage damaged by severe cold snaps. In our garden it therefore does better placed in a spot that doesn't warm up too early.