Up here, mid-Minnesota, and the part of Minnesota one lives in determines how much care should be given to Hybrid-Tea roses.
As I said temps. in my Southern garden rarely reach -30, go fifty miles north and add minus ten degrees go sixty miles south and subtract minus ten degrees.
It is standard and recommended that if one covers one's roses , not buries but covers, that the ground should be frozen hard before covering. Than means temp. into the low twenties to high teens.
Approx. ten years ago we had below zero at both gardens by Halloween; I was out laying sod in a snow storm the day before the sub-zero hit.
My uncovered roses survived and a few weeks later I was mowing lawn again.
The fact that there was a foot of snow on the ground probably greatly affected rose survival.
Potted roses vs bare root are the most likely to die. After I quit buying potted roses my loss rate declined a good deal.
This is from experience, if you get that hard a cold snap in the spring, you will lose some roses -- without -- exception.
Now how hardy the rose was obviously comes into play but there were years that a rose I thought might go belly-up did not but one that was tough as nails died.
I used to go to rose seminars and the main answer from the experts for the reason why was, you are not the first person to say this to me but if you are growing roses up here that are out of the recommended zone no matter how careful you are it is still a crap-shoot.
Some defy logic.
If you get a cold snap after uncovering, all, one hundred percent of the sprouts will be dead so your roses will again be starting from zero and be blooming weeks later than they would have without the cold snap.
Some times the sprouts die on some canes even without a hard cold snap.
As the gent told me, it is a crap shoot.
It is only in the past decade that I switched to burying roses verses simply covering them.
My loss rate after that, except by me doing something really stupid, is now near zero.
My last great loss came when I moved some roses to go from two beds to one down south, moving old roses is risky and most of the ones I lost were over ten years old.
If you have never covered your roses due to sub-zero winter temps. it is hard, nor do I expect you , to understand what that amounts to.
For years I did like mom and simply cut the roses down to about eight to twelve inches and piled on three feet, loose before it settled, of preferably Oak leaves.
When uncovered in the spring, depending on how late one uncovered them, the top inch or three would be black from winter kill so you would trim that off.
If you left them covered long enough, they would be sprouting under the leaves.
You would know which ones were in trouble by how much black was on the canes; sometimes, ones where you cut them down to the main stem because the canes were almost totally black would sprout new canes and do well, while those that seem to be OK, would die back and in a few weeks be dead; although you had to leave them for at least a month because sometimes about when you were about to pull them, suddenly out would come sprouts and by the end of summer it would be blooming true to form.
I then tried putting fabric over the trimmed roses and did not trim them down as low as before.
After that I piled leaves over the fabric.
In this method the roses were further along in sprouting to leaf out than they were in the old method but removing leaves from the fabric with a fork became an annoying hassle as the fork tines would pierce and hook the fabric that was off the ground near the rose bush due to the height of the rose bush.
You would get a nice fork full of leaves lift it and end up dumping it over because you had hooked the fabric and it pulled the fork from your hands.
That is when I used the method my neighbor down the block had always used, totally burying his roses.
At first I did just some and when they always looked better than the ones not buried I now do almost all.
The ones I do not are located where burying is hard to impossible but I place loose dirt over most of the plant after cutting it down.
I do put fabric over the buried roses up north as the bed is on the edge of a hill where wind hammers it often.
I also put a fence of wire around the bed to a height of four feet so the deep leaves will not blow away.
I used to use straw or hay bales but bales prices have soared and I got tired of storing bales all summer.
AS an aside.
I feed my squirrels all winter and used to give them peanuts.
Well one spring when I picked up the bales, which were on the ends of the garden, underneath was a path of tunnels in which some were stuffed full of peanuts lined up end to end.
I never saw them but there were probable some rather porky Meadow Voles around some where.
Crown gall took out the last of mom's very old roses which is one reason I stopped using one rose bed now have all in the unaffected bed.
I treated the roses roots and all.
