Question
Hello sir, could you please advise me if I should dig up two
hibiscus trees that I planted in the summer and has bloomed for
three months solid and bring them in the house. I live in
northern New Jersey and the nursery where I bought them told
me I should not have planted them in the ground and instead
should have left them in pots and then bring them into the
house. These two trees are about 4 foot tall. I actually have a
third (6 feet tall) tree that I left in the pot after hearing the
advice from the vendor. I somehow think if I were to wrap these
trees in burlap or something, that they might survive the winter
in the ground. My wife says we really don't have the room for
these trees indoors. Please advise. I thank you in advance for
your time to answer.

Answer
Robert,

Your local nurseryman is correct.  The hibiscus you have are hardy to zone 8-9 and New Jersey is zone 6.  Wrapping these plants in a down jacket will not allow them to survive outdoors.

Depending on how much you spent, if it was not alot, consider these plant annuals (I know this sounds harsh).  

Good luck

Gary