There's a problem with "rubber tree plant, " a name used for several plants, some of which are not that closely related. Some of them are figs, Ficus, and they don't look like any of the other figs or other unrelated plants also commonly called ficus even though they ain't really Ficus ( note the f vs the F). Some of them actually are the Asian or South Amaerican rubber tree, which are two different trees,some of them are close relatives of them but don't look anything at all like them. They're all called 'rubber plant" because they look, feel, grow, and, uh,,"act" like rubber plants. Some of the "rubber plants" will do fairly well even farther north, some of them don't stand a chance even in southern Florida. Sometimes it's got more to do with the tropical near equal day night cycle than temperature. Without a description or a more specific name , the only advice I can give you is take it to a local nursery with licensed personell and ask them what it is and if it can live in the ground. Having said that, your plant is probablly one of the more common ones sold as rubber plants and should do fine outside. If they can keep banana plants in the ground outdoors year round for several years in your area, rubber plant should be almost as hardy (disregarding the differences in life cycle between 'nanners and rubber). A cold snap may require some extraordinary precautions, like the citrus growers use. Beware, rubber trees can grow a couple hundred feet high with a limb spread of a a hundred or more feet. Also some of the Ficus 'rubber plants' are close relatives of the strangler fig and can put kudzu (hmmm, one of whom's names is "rubber vine" and there are efoorts to use it as a source of rubber) to shame, outdoors it's liable to 'lay down' and spread runners each of which wants to climb other trees, it's called 'strangler' cause it climbs other trees and literally squeezes them to death. If it's too big for the house and ya gotta do something, like put it up for adoption or send it to boarding school, put it outside, whaddaya got to lose?

I live in West Central Florida and have two planted outside on the east side of the house. They are about 5 ft. tall now. They just flourished when I put them in the ground. I do cover them in the winter when we are warned of freezes.

Why would you plant a rubber tree?