I have Owari and for me it bears in November to December. I'm sure ripening time will vary. Owaris can be larger (like double) than Kishu. My Owari tends to bear well every other year. I like that the fruit start to ripen when it's still outdoors.

While i have a Kishu, it is way too small to bear, so no experience with it yet. But I think it bears somewhere in the Dec - January range.

Both are tasty!

Doubtful any really thrive on a short growing season, but if your sunroom gets LOTS of sun and you can keep the temps cool in winter -- like in the 40 to 60 degree range, you should be good.

Your call.

I have an Owari tree, and once had a Kishu. Between the two I would choose the Owari. Both taste very good. My problem with the Kishu is that is so tiny. The Owari is a much larger fruit. I once had a Kishu tree but tossed it out because the fruit was too small to mess with.

Genetic studies done in Japan have actually revealed Kishu to be one of the parents of Satsuma.

The other parent was a now obscure Japanese variety called Kunenbo, basically a large sized very aromatic tangor-type mandarin that contained a lot of seeds, and in old times was the most popular variety in Japan before Satsuma (unshiu mikan) came into existence 400 years ago.

"Satsuma" is so called because the southern tip of Japan was once a province known as Satsuma, and that was a popular growing region for mandarins due to the climate (and probably its proximity to China also, since these citrus varieties came to Japan during China's Tang Dynasty).

(The pomelo would not reach Japan until a little bit later, and that came from a Cantonese sea captain who was sailing from Taiwan. This was probably because the region of China closest to Japan where those other mildly hardy varieties came from was a little too cold for growing pomelos)

Kishu are small in size but still very easy to snack on because they have loose skin and are effortless to peel.

They have excellent flavor, in my personal opinion, although not quite as good and aromatic as Satsuma.

I would say in terms of type of flavor, they are both in the same family, different from the other standard mandarins. You really cannot go wrong with either. I would say they are both in my top three or four favorite mandarin varieties.

If you're concerned about growing season, the St. Ann and Xie Shan varieties of Satsuma both ripen slightly earlier than standard Satsuma. But those can be harder to find.

I prefer XIE SHAN, if you only grow one or two trees. A lot depends on their bloom start. Late bloom, late ripening, ( second bloom). Hard to beat taste! This is a combo tree, Xie Shan yellow, green fruit are Shiranui.

I have a Kishu and im thinking of tossing it actually Since I first got it the last couple of years it hasn’t really given me great fruit it’s been a little dry but very sweet Not worth the trouble for its size but if I had the space I’d keep them both To see if it gets better by its fifth or fourth year, however If I really had to choose I’d choose an owari as long as you know they don’t give great fruit until the fifth or fourth year I hear!