Hi Lavender, I grow Scepter'd Isle as a tree rose. I store it over the winter in my unheated garage, wrapping the trunk graft in bubble wrap. It has made it through two winters now, but I am in zone 5. It is a lovely rose and a generous bloomer.

I grow it as an own root in zone 5, and it has come back nicely after our winters. I think that most if the Austins are rated zone 6 as a general default zone, but a lot of people grow them farther north. I would ***guess*** that with mulch, it will be okay in zone 4, but it is just a guess. Donna

I am zone 6. SI laughs at winter here. Even when we get down to 0, there is little die back. I provide no winter protection. SI is a favorite here. It has a very strong myrhh scent.

{{gwi:224173}}

I am in Texas so cant comment on hardiness, but it is a beautiful, arching shrub and has lovely blooms with that nice myrhh scent. I really like it!
Judith

I can't really speak to your winters but this is one of my favorite, favorite roses. Even my Husband says it is gorgeous and he is not a gardener.

I will remind you, though, that Austins can't read and it is well over the described height of 4 or 5 feet in my zone. But healthy as a horse.

I have had no problem over-wintering Scepter'd Isle in Zone 4. I mulch the base of the plant with a few handfuls of cedar mulch. Like the other comments, I too am impressed by this rose.