I have two and neither had problems like yours. They did get eaten by Cuban beetles last year but came back fine. My Sweetheart and Moricius (sp?) are pretty hardy. I think it's because most everything in my yard that likes fruit trees attacks my guava or canistel.

What did you treat them with? I think they're pretty hardy and will rebound.

BTW, I've had my two grafted trees in the ground going on two full seasons and not one single fruit but plenty of growth.

We have not had enough cold for the last two years. Most lychee varieties have not fruit in SoFla for a while

I am very hopeful about this year with the nice cold start

It must be just terrible to not have enough chill hours....