Hollyhocks are kind of scary to trade in my opinion. I have transplanted some from my mom's garden and some make it others don't and that is just 1 hour out of the ground, they wilt real quick, but I know people that want them and do trade for them, so maybe they know something I don't. your right they are easy to grow from seed, but some people are impatient for blooms sooner rather then later or maybe they just don't like to grow from seed. good luck!
micke

I'd recommend against it. Mature hollyhock plants have several major taproots (not a fibrous root system) which you will almost surely sever digging them up. I don't think they would mail well and survive.

I will only send 1st year HH's in early Spring.. once the tap root gets going they don't like moving... Same with Lupines.

~Dusty~