The best part with pots is you can move them. You can change camera lighting from sun to shade. You can turn the pot and get different angles to really capture that diamond dusting off the sunlight. So many perks to potting or temporary potting. I placed a new one or 2 on my porch every bloom
I also took some to the other garden site and made a few crosses.
I left my babies completely exposed to the elements. I experienced minimal heaving in the winter, but did notice a lot of West coast rhizomes cracking from extreme lower temps of winter. In the spring i saw well drained pots flood from heavy rains that needed tipping over. It was a soap opera at times last season.
As I still try to figure out how to deal with the element of natural soil here I prefer to pot. You almost can't go wrong
Just make sure it's big enough because those roots grow insanely long really fast. Potting was a iris life saver for me. Hell, I didn't even have a true garden till this year and it's mostly made from those potted.