Hi Sheaper,
Growing your own Satsuma is definitely worth it, not only for the satisfaction of 'doing it yourself', but because tree ripened Satsumas fresh off the tree have far better quality than the ones you get in stores, which tend to be picked on the green side.
I've never grown a Satsuma from seed, but have grown a Changsha mandarin. It took about twelve years to bear fruit, but in my location the growing season is quite short compared to the Southeast US, so I usually only get one complete growth flush in a year, with sometimes a second incomplete one, whereas, in your location, you should get two or three. So, Millet's estimate of 3-5 years is probably more accurate for your tree from seed.
In my location, which is about 750 miles north of your latitude--depending on which part of South Carolina you are--winters are more brutal than yours. Freezes where the temperature stays below freezing for up to ten days, with low temperatures down to roughly 10F, occur once every five or six years on average. Satsumas will not survive this, so I use the shelters described above by SoCal for them, plus a string of the old incandescent Christmas tree lights on a thermostat, to keep their temperature above freezing. Usually, though, the temperatures are not that cold, so I leave the shelters open to prevent mold, and only close them and plug in the lights when the temperatures look to drop below 28F when fruit is on the tree, or down to the low 20's when the fruit is harvested. This occurs, on average, only about a dozen days a year--more often during the rare arctic blast.
I have, however, tested unprotected Satsumas. When I first started my citruholic adventures twenty years ago, I found that only the earliest ripening Satsumas reach full size and maturity here, where our growing season starts in May and ends in late September. The Owari and Brown Select Satsumas never grew beyond golf ball sized, and did not winter over to resume growing the following spring. So, in 2014, I decided to sacrifice them to the frost gods. Sure enough, in November 2014, the Veterans day storm came, with strong east winds of 20 mph, gusting to 50 mph, and where the temperature dropped to 18F and stayed below freezing for 36 consecutive hours. This killed both three foot trees, although the Brown Select did push out a small shoot for about a month before giving up the ghost.
Then, last year, I left a very large Okitsu with a 1.25 inch diameter trunk on a citrange rootstock, which was outgrowing its shelter, exposed to the elements, after replacing it with a dwarf Okitsu on Flying Dragon rootstock in a different location. Sure enough, last winter I had three short arctic events down to 18F, each accompanied by high east winds gusting to 35 mph. In the December event there was a 36 hour period where the temperature never rose above 22F. This killed the Okitsu. Interestingly enough, last winter also killed a small Keraji mandarin on FD rootstock, even though it was protected by a styrofoam box, although a larger Keraji on a Citrange rootstock survived with 70% damage. Kerajis are reputed to be hardier than Satsumas, but apparently not that much hardier.
So, the conclusion of this bit of a ramble is that you should be prepared to protect you Satsuma if your temperatures drop much below 20F, if it looks like it will last more than a few hours, although in your location a tarp may be enough.
Hope some of this helps.
Jim
