[Ozzello]

That may be true for the other zones, but not for zone 9. When something is tagged zone 10 and warmer, it EXACTLY means, it will die from the cold in the next zone up. Yes a very few of those SUB Tropicals can make it through our milder winters, but over time, those average winters, and harder winters will arrive and take them out.

The changes in the northern zones (8 and lower) you can cheat to the north a zone or 2, but not here, where we ride that line between Temperate and Tropical.

To freeze or not to freeze... it isn't a question. When dealing with zone 10 plants, it is NOT to freeze, and zone 9 freezes. Unless by "care" you mean, HEAT the tree (no I didn't say cover) or build a greenhouse over it. (That was commonplace during the winter for people with tropicals in the yard just 2 decades ago) Your crotons, areca palms etc, are going to die if they freeze... that is why they are called TROPICAL.

I have a lot of respect for the Master Gardener's garden club folks, but let's not pretend that the moniker isn't more about participation in functions and donating a bit of time to the club. Compared to a college degree or actual masters in horticulture, it is just a club with not much of a scholastic requirement.