My plumeria is going on three years old. I haven't had any blooms and I was hoping this year would be the year. But when I went out today, I noticed the bottom of the stem looked really weird. When I knocked the surface with a knife, there was no milky white substance. I have put it out for a few hours at time but when the temperatures exceed 90 degrees, I place it in the shade. I also use fertilizer once every two or three weeks. I don't really know what I have done wrong, other than I might have watered too close to the roots. I am still getting new growth and lots of leaves are coming in. I would like to know what this is and how I can fix it without it killing the whole plant. I have attached two photos showing the base of the plant near the roots and two photos of the ongoing growth.
