Larry Blanchard wrote in message ...
In article ,
says...
I'm in zone 5b in Canada and have more than 100 Austins (grown on
hardy northern Ontario rootstock) that get no winter protection except
for a blanket of snow. My oldest ones are six years old and while I've
even had Rugosas suffer winterkill, not one of my English roses has
ever died or gone wild, even when the temps go below -30C.

I've had dead branch tips on both rugosa and English roses, but never
total dieback of either. I did lose a moss rose and a Dortmund due to
cold weather, both in the same year, and a white rugosa (Sir Thomas
Lipton) sucumbed to something or other, probably thrips.

Interestingly, I planted two rows of Therese Bugnets my first year in
the house and what wasn't killed by winter failed to thrive the next
summer. I ditched the supposedly hardy roses and replaced them with
Rugosas, which stand up to winter, drought and the herds of deer that
view them as a salad bar because with better than 200 bushes, life is
too short to deadhead. Like you I have dead tips and quite a few dead
branches that have to be trimmed come spring, but the roses are so
tough and sucker so prolifically that they have kept their shape and
they're six years old. A spring prune, two shovels' worth of manure
during the summer and they're reliable little flower factories. A
terrific rose.

After several years of experimentation with my Austins, I find the
best winter strategy is to trim them down to nothing in November –
they bloom on new wood and clearing out all foliage and old wood in
the fall has greatly reduced the mildew, blackspot and caterpillers
that overwinter in the beds. I leave my spent annuals standing to act
as snow collectors to insulate the roots and take them out come
spring. I started doing this last year after experimenting with spring
prunings etc. and this method is the best I've tried. It's -25C
outside today and the Austins are as cozy out there as possible, under
the circumstances. Too many sources tell you Austins aren't hardy
enough for northern winters, but I find they require less attention
than so-called hardy roses.