Bought a beautiful yucca cane about 3 weeks ago. It has slowly started to brown at the tips and has little lighter spots on the leaves. There are two stalks – the one on the top is definitely worse, although the leaves on the lower one are starting to brown a little as well. See image of top leaves here: http://i.imgur.com/XFPVjxS.jpg The first two weeks I had it it was in a chilly room 60-65 degrees F. I have had it in indirect sunlight, I may have over-watered it. Anything I can do to save it? Thanks!