What a find! I keep checking our stores, hoping they'll get some in.
What I do with these is take them out of the pot and completely bare root them, verrry gently. There will be 4 or 5 plants in there, and if roots are really intertwined, I leave them together. I repot them in a good planting mix in separate 1 gallon pots. I set them outside as soon as we're into 50s at night, and let them grow a bit. Later, I plant them in the ground, giving them about a square foot apiece. I have some that have been in my garden for 7 years now. It drives me nuts to not know the names!