I lost all my potted daylilies this past winter/ spring. I actually think it wasn't winter that killed them, but the rapid, early & hot spring followed by frigid April. I also lost some in the garden, but it was 100% loss of potted ones.
Never again. Even if it is in temporary spots, all will be planted in the ground.
Unfortunately, I never heard about tipping the pot on it's side until AFTER I lost my potted ones.
My plan was to let some tender ones overwinter in my garage it is insulated & I have grown plants out their in the past. But the daylilies got aphids and rust - and so I put them outside ~Jan