In or around August, I planted a young orchid tree about six feet tall. It went through a little heat stress during the August-September heat, but flourished once the weather cooled down. About two weeks ago, in Tucson, it got to about 24 degrees for three nights in a row, mid-50's during the day, and then warmed back up. I did not cover the tree like I probably should have. The young tree has lost all its leaves. As you can see, the stem is fine but the branches have turned a red-ish color. I know localized discoloration of hard wood tends to mean localized death. I called the nursery, and he said since the tree doesn't have leaves it cannot feed itself. He told me to mix cane sugar with warm water and soak it deep into the roots. I just did that. He told me to begin fertilizing in about a month. He said even if the branches did die, it will grow new ones, possibly on a split trunk, and become a fuller plant.
Based on the picture, where you can see the red discoloration, does anyone have any suggestions? How/when should I prune the dead branches. Do the branches appear dead to you? (I scratched the trunk with my nails and its green, the branches are brittle though.)