Hardy Hibiscus problem

I have two Lord Baltimore hibiscus in my garden. One of them suddenly went brown about a foot up the main stalk and the leaves and blooms shriveled and wilted. I cut it back to where the stalk was green and it's alive and growing, has new branches coming out.

The problem is - in about about a month or 6 weeks we will probably get our first frost. Now it's got all this new growth and I'm worried that what I've done may kill it. Should I cut the plant all the way down to the ground just before frost? I'm not sure what to do. Also, my other one is still quite tall and blooming - do you just let the frost make the plant die back? And do you prune it after that happens? As you can tell I am a newbie when it comes to hibiscus. I want to take care of them because they have been lovely in the garden, I sure don't want to lose them. Thanks for any advice!

Hi there. I love my Ld. Baltimore, too.
Don't worry about the tops of your hibiscus. The freeze will cause them to die back but the roots will still be happy and go dormant until next June(ish). I cut mine back to the ground with my tree loppers. You might want to leave a few inches of stalk as a marker just so that you'll know where your hibicus is planted. They tend to be very late emerging in the spring. When I bought mine, 2 different people warned me to be patient and not dig them up thinking they were dead.
Hopefully, this gives you a small idea of what to expect.

Thank you for letting me know what to expect. Yes, tree loppers is what it will take - the main stem is very large. I will not dig them up, but I'm glad you warned me to be patient. I can see how people might think they were dead, since it's so late when they come up.

But they are definitely worth the wait!

I've actually had to use a saw on mine! LOL.

Showme -- Lora is right. You need not worry about the tops since these die back to the ground during the winter. Mine don't start to emerge in the spring until mid to late May, but as you know -- they grow very quickly!

The Lord Baltimore flowers are magnificent!