'Kingsville' is used A LOT in bonsai. I've recently found out that there's a Thai boxwood that may be far more tolerant of indoor culture. I tried Kingsville. No dice. I've a feeling, though it was more due to humidity that temperature. The specimen I received was exceedingly small (less than 1" tall) and it was in pure Akadama. It was already doing poorly when received, so I didn't want to repot it. It struggled for a year, but I gave up before it did. Maybe if I have more room someday I'll try this (and other "difficult" species) again. Otherwise, boxwoods belong outdoors.