Many years ago I operated a wholesale nursery in Northern California. The weather had hot summers and fairly mild winters. It was notorius for late season warm temps in the 80’s and again early warm temps in the 80’s. Every year the weather would stay warm into November and a freeze would come and I would lose plants. Again, every February the temperature would warm, everything would bud out and the temp would drop and I would lose plants. One year between the fall and winter I lost $50k worth of plants! Now I grow Flowering Shrubs and Natives in Colorado at 6300ft. and the temperatures I guarantee are cold.  Many of the plants I grow now are the same as I grew then. But these plants are taken from stock that survives the winters here and the plants produced  survive the harsh winters. The weather here has been in the upper 50’s and 60’s for the last couple of weeks and everything has started budding out. But now the weather has returned to lows around 10 and highs in the 30’s. But the cold doesn’t effect the plants. Plants grown in mild climates like California can be unable to the survive harsh winters that many states experience. This is why I chose the name ColoradoHardyPlants!