We are new to a mountain area in SoCal; winter temps get into the teens (F). How long do we have to plant this year--can we keep going into the winter or should we stop at some interval before the first frost (~ end of Oct.). Of course, I am using cold-hardy plants. but they will come from nurseries at lower altitudes (= warmer climate).

Even genetically cold-hardy plants would, I assume, need to be acclimated to the greater cold they will experience here vs. where they were grown. Can we buy the lower-altitude plants and acclimate them up here before putting them in the ground? How long should we give them to adjust? Presumably we would have to provide shelter at first (especially if it's started freezing up here).

Thanks very much for any help.