Technically, tropical plants are not resistant to frost or freezing temperatures. But the rules can be bent a little when you grow certain plants that look like, or are related to tropical plants that cannot survive the cold. Some varieties of palm tree, for example, are hardy, and some species of banana will come back from the roots after cold winter temperatures kill them back to the ground.
Tall and stately, the Mexican fan palm can withstand temperatures as low as 18 degrees Fahrenheit. They are almost an institution in Los Angeles, where they have grown very tall over the 100 years since they were planted, and they have survived many winters where frost has covered the lawns of this Southern California city. Other palms that are frost-hardy include the needle palm, the Mediterranean fan palm and the windmill palm.
Hibiscus, Bird of Paradise and Lantana
The hardy hibiscus, or Rose of Sharon, is grown in many areas that receive hard frosts. Birds of paradise are hardy down to 15 to 20 degrees and survive well if they are grown under the protection of a house's eaves. If they are unprotected from frost, any blooms will shrivel and die, but the foliage is normally unaffected. Lantana, an ornamental flowering plant, is often damaged by frost, but will renew itself when temperatures rise.
Guavas, Figs, Passionfruit and Bananas
The pineapple guava is often grown in gardens as far north as the San Francisco Bay Area and is tolerant of relatively cold temperatures. Fig trees are deciduous, and during one cold snap in Phoenix, Arizona, no damage was reported. Some species of ornamental passionfruit will tolerate frost. The fruiting varieties are more frost tender. Ornamental bananas can be grown outdoors as far north as USDA zone 8: they will die back to the ground during freezes, but if you mulch them in the fall, many will come back the following spring.
Some orchids, such as the cymbidium, can withstand winter temperatures. If an unprotected cymbidium is in bloom when frost hits, the flowers will die, but the foliage is safe down to about 18 degrees. It's best to cover or move orchids indoors when cold temperatures are forecast.
Although the avocado is a tropical fruit tree and young trees can be killed by frost, older trees can survive a light frost. The Bacon variety is the most cold hardy, enduring temperatures down to minus 5 degrees Fahrenheit.