The week of Jan. 10 we planted two Sabal Palmettos in our northfacing backyard. They looked great!! By Jan. 27 the leaves began fading, turning yellow then brown and drying to the point where they've become brittle. This began with the lower leaves & spread upward. The heart/spear of one seems ok, but the other one seems limp. We've been told it's watered too much, it's not watered enough & it seems no one knows what they're talking about. When we planted them we kept in mind not to plant them too deep or shallow. I've stuck a probe into the soil & it's soft til about 12"-14". Watering/irrigation info says trees here should be watered to a depth of 24"-36". These changes began before the frost we had last week. Today several of the cut stalks that remained on the trunk came off easily. Does anyone have any suggestions? Thanks.