You're probably not doing *anything* wrong. Jade plant (
Crassula ovata or
C. argentea; also sometimes sold as
C. portulacea), according to the Sunset
Western Garden Book, is suited for mild-winter areas. I've also read, in newspaper gardening columns here (don't remember when, but prob. late '80s/early '90s, before Internet), that it takes a certain amount of December sunlight to trigger flowering, which takes place in the
winter.
My jade plants' flowers are fading now. I hope they enjoyed all the rain we had this year; 200% and then some of normal, I think. They must have gotten all their sunlight in December and early January, because there was precious little available after that until this very week. *whew*
Sunset also says that "Most [Crassulae] are from South Africa. All have succulent foliage, and many have strange geometric forms. Need good drainage. May not survive winter without overhead protection in Zones 8, 9, 12-15, 18-21." (These are Sunset climate zones, obviously; they "achieve" below-freezing winter temps regularly.)
I imagine that the combination of bright winter sun + mild outdoor temps is hard to come by in the more northerly latitudes of our country; there are winters when even my jade, at only 37 deg North and infrequent freezing temps, doesn't bloom.
Please don't beat yourself up if your carefully tended--and long-lived!--indoor jade plant hasn't bloomed for you. You're doing a good job with the conditions Mother Nature has handed you.
Cynthia H.
Sunset Zone 17, USDA Zone 9