Dividing hardy hibiscus

[LauraMoser]

I've never had these flowers before, therefore I don't know the proper care. They came with our new house and now that they are blooming, they are gorgeous!

Anyway, my friend asked me today if I'd be willing to give her some, which I'd be happy to do as long as it won't affect the plant and as long it will multiply.

So, I'm in south central PA (zone 6A), its midsummer here, and they just started blooming within the past week. Is it safe to divide and transplant now? And they will multiply right?

I'd really hate to lose the whole plant by transplanting at a bad time. They are gorgeous, and I know they are quite expensive to buy around here!

ETA: She wants to trade me some of her jade flowers for the hibiscus. I've never had those before either. Is that a fair trade?