Thats too cold for my southern a$$,but I might welcome -20 when we hit the triple digits,sometimes my AC is just not cold enough.I left Indpls cause hated the winter.I couldn't even warm up enough in the summer...lol Hated snow& snow trucks
most
roses...
dig hole 1 1/2 ft wide 2 ft deep ammend the soil removed.I use cow manure/peat moss sometimes saw dust if any being cut. I keep watered daily at least 2 weeks then will fertilize unless comes in pot not bareroot.
For me it seems the ones bought bareroot start slower than bought in pot...with the acception of Our Lady of guadalupe.she's
growing same pace as contanier ones,shes a floribunda she gets total full sun.not a bit a shade (well maybe the grass I weeded from her roots yeasterday)
Thought.Raised beds soil warms faster& will drain faster as well