Hello tropical people! 4 or 5 years ago I planted some seeds from store bought Longans and one of them really took off. I'm in zone 7 (North Carolina) so it and all my other tender fruit trees have to spend the winter in a hoophouse I seal up like a greenhouse and keep above freezing. Last summer this tree got so big I had to really cut it back in order to squeeze it through the greenhouse door. So now it is pushing out a lot of new growth and one of them appears to be blossoms. I don't know if it will actually make fruit while living in a pot, without anyone to cross pollinate with.
Very impressive, indeed. I wonder if you have a seedling that is just precocious or if good growing culture....getting the tree to some size and then having the cold caused this. In any case it is a beautiful thing. I did fruit a seedling a number of years back and while I do not specifically remember now how long it took from seed to flower, I am quite sure it was at least a decade, may have been a decade and a half. My tree did set fruit on its first flowering. I believe mine is a Kohala seedling.
Looking back to the old GardenWeb post on this subject I found this:
hmhausman(FL 10B)
June:
I planted out many longan (and other fruit tree seeds) when I was new to this hobby many years ago. Most of the seedlings died, or got pot bound eventually and turned into unintentional bonsai specimens. However, every once in a while, one tree caught my eye and seemed to be calling to be planted out in the yard. One such tree for me was a Kohala Longan seedling that I stuck in the ground approxiamtely 15 years ago. Here's what the tree looked like this year when it fruited for the first time.
On 7/2/10
(to see pic, go here:
http://forums.gardenweb.com/discussions/2188147/18-longan-seedlings?n=11)
I didn't take a picture of the hanging clusters of fruit in early August, but suffice it to say that there were 10 pound clusters of fruit hanging heavily on the end of virtually each and every branch. The fruits were nicely flavored and very sweet. There was not a great flesh to seed ratio, however, and I am not sure if that was because of the characteristic of this particular tree or whether the heavy clustering limited the flesh production. I will try next year to thin out the clusters by hand to see if i can get the fruit to size up more and give a better ratio of flesh to seed. In any case, having it fruit for the first time was very exhilarating. BTW, this tree was totally blown over and uprooted by Hurricane Wilma in 2005 and so there was some major limb damage that has kept the tree somewhat manageable in size. For perspective, that is a 5 foot tall chain link fence between the tree. Good luck with your young seedlings.
Harry