I have a 3' rosemary cone topiary that I brought inside about 2 months ago when the nights started to get really cold and it is not looking good at all. I have it in a fairly well lit room between an east facing and a west facing window, away from any drafts and heating vents and I've been supplementing with a growing light, all to no avail. It started out looking a little powdery on its needles and when I called the nursery I got it from, they suggested that it could be powdery mildew and to spray it down with a baking soda solution. Yikes! I don't know what happened but it looks even worse. The needles have started to become dry and brittle and some of the tips are turning brownish-black and curling. It looks like it's dying from the bottom up and even though I top dressed the soil, the base of the plant seems to have a sour smell!! Yuck. I watered it frequently as I had read that it did not like dry conditions and misted the leaves a few times a week, but now I'm afraid I overdid it. Am I too late to resuscitate my beloved rosemary? Any help would be greatly appreciated!