I have 18 trees lychee trees with 8 different varieties planted. I got 10 pounds of fruit last year. Based on the current tree size, I could be getting a few hundred pounds. They flowered well but there were lots of males and rainy weather during flowering caused fungus issues. I have a wild honey bee hive squatting in my barn so pollination was not an issue. My longan trees produced even less. If I could do it over, I would take a different approach. It is relatively easy to buy lychees from local growers. They don't taste better when you grow them yourself. I would recommend using the yard space for something that cannot be easily sourced locally, tastes better when home grown, or minimally is consistently productive.