Osmanthus have become so popular that many gardeners want to grow them outside of the zones for where they are comfortable. Many gardeners look on a hardiness zone map and see that many Osmanthus are hardy to zone 7. Plants can take a quick dip to a very low temperature, but if it warms up rather quickly, there will be very little if any damage. But if the temperature stays below freezing for an extended period, even if it is not extremely cold, the plant may experience damage or even be killed.