Parts of my roses where the dirt I hilled them with for winter have washed away and started to sprouti. Should I unhill the rest of the roses plants now due to the unseasonably warm weather?
Thank you for contacting Toronto Master Gardeners.
We have had an unusually warm winter this year. It is not yet spring and temperatures in Toronto are already much higher than historical averages. This has resulted in plants such as roses beginning to sprout much earlier than usual.
However, there is no guarantee that spring is fully here yet. We could see cold weather and snow again before warm spring weather is here to stay. To wit, nighttime temperatures are forecast to fall below freezing to -3 C in many Toronto neighbourhoods next week.
I would rely on the guidance of the Canadian Rose Society regarding when to remove winter rose protection (see link).
In late spring, when the soil has thawed and a hard freeze is no longer expected, carefully remove soil mounds from established plants so as not to damage any shoots that have begun growth.
So, I would recommend very gently re-covering your exposed roses with soil, back to the winter level, so as to cover any new growth. I suggest you only remove this winter protection once the soil has thawed and there is no risk of a hard freeze. A hard freeze, one that will kill plants, generally occurs when temperatures stay below -2 C for two or more hours (see link).
Hope your roses thrive this season.