SoCal2warm, I think I can shed some light on Millet’s point about citrus forming flower buds over winter: we learned at one of the south east citrus expos that citrus need some chill hours in winter to bloom in spring, similar to peaches or apples; however, unlike peaches or apples that may need 200 to 400+ chill hours below 45 degrees, a citrus tree only needs a few hours below 45 degrees to bloom. That made me think of the climate of south central FL where I grew up, which is where citrus thrive without care, before greening came around that is. Citrus might be able to survive and grow at a high latitude with winter protection, but that doesn’t mean that citrus is happy or will be fruitful at high latitudes. For those of us in cold winter climates, If we can create a climate for the citrus that resembles their native or natural environment, they will perform better than if we subject them to prolonged cold temperatures. If you’re at such a high latitude that citrus outside stops all growth or goes so dormant that it has no hope of blooming in the spring, it’s probably going to die anyway like it would in Siberia. For example: a satsuma planted outside without protection where I live in western NC might as well be planted outside in Siberia without protection; the tree won’t make flower buds for spring because it’s gonna freeze to death.