Hi folks - I purchased (at great cost!) three large black bamboo plants and set them in pots on my deck this past spring. This winter has been exceptionally hard on them; they have lost more than half of their leaves and the ones remaining are quite shrivelled and pale looking. I'm afraid the winter frost/snow/cold has done irreparable damage. I'm wondering if anyone can suggest aid at this point - I'm willing to try anything to save them.